The East Coast Greenway (ECG) is a multi-modal transportation corridor currently being developed for bicyclists, hikers and other non-motorized users, extending from Calais, Maine to Key West, Florida. Further information regarding this facility is available on the East Coast Greenway Alliance’s website at www.greenway.org. A 259-mile length of the Greenway extending through coastal regions of South Carolina was evaluated by a study team, comprised of The Citadel, Clemson University and South Carolina State University, to assess route conditions and address other route planning issues within a seven-county coastal area.
An extensive Geographic Information System (GIS) database was assembled within the corridor to evaluate transportation issues, bicycle suitability, alternative route comparisons, facility needs assessment, route continuity and improvement recommendations. The total database consists of 137 sections and 450 segments, with the modified existing Greenway route, reflected in route maps and route tabulations, consisting of 72 sections and 234 segments. Various sections within the corridor require the Greenway to extend along existing roads and a primary concern occurs when non-motorized and motor vehicle traffic operate in close proximity, within a common right-of way. A Bicycle Compatibility Index (BCI) Level of Service (LOS) procedure developed by the Federal Highway Administration was used to evaluate geometric, traffic and landuse conditions along route segments. In addition, GIS coding of the route allowed a variety of useful tabulations describing existing conditions along the SC East Coast Greenway.
Study results and findings include the following:
Table of Contents
List of Tables
List of Figures
I. INTRODUCTION AND STUDY OVERVIEW
Plans for development of the East Coast Greenway (ECG) in South Carolina have been underway for the past decade. Initial efforts produced an overall corridor map, as shown in Figure 1. While this map identifies planned and completed facilities, along with general linkages between major destinations, specific details of future off-road path locations and interconnecting on-road segments were purposefully left for local and state government officials to address, within the context of their normal transportation planning efforts. Currently, studies are in progress with the aim of developing a master plan for proposed Greenway facilities structured within the framework of three coastal areas of South Carolina including; Lowcountry, Berkeley-Charleston-Dorchester and Waccamaw regional planning districts. Routes evaluated in this study were coordinated with on-going efforts in each district.
This study focuses on evaluation of the SC ECG, as it currently exists, and includes other readily apparent alternate routes within the corridor limits depicted in Figure 1. Since only small portions of the planned facilities are completed, most of the current route connections are situated along existing roads. In taking a multi-day trip along the Greenway today, as many cyclists are already beginning to do, most of the linkages would be made on existing roads. Once master plan studies are finalized, proposed off-road path facilities are likely to be built in stages, and traveling extended sections of the Greenway will continue to rely upon on-road connections for many years to come until future projects are funded, designed and constructed. The Bicycle Compatibility Index (BCI) Level of Service (LOS) procedure, developed by the Federal Highway Administration (FHWA) (1), was used as the basis for conducting route evaluations. Results of this study are intended to help planners and transportation officials gain a better understanding of the current Greenway status and tasks required to implement needed improvements within a systematic and time efficient manner. An overview of tasks conducted for this study is provided in Table 1.
Table 1 – Overview of Project Tasks
II. LITERATURE REVIEW
Evaluation of bicycling conditions and level of service has been addressed from two fundamentally different approaches over the past decade. The first approach is based on determination of capacity and LOS for bicycle facilities, multi-use paths and bike lanes predicated primarily on flow parameters. This approach is useful in determining how many cyclists, pedestrians and other path, or lane, users can be accommodated by a facility of a specified width. Methods for these type procedures were developed by Botma (2), Allen e.t.a.l (3) and others. The results of which are compiled in Chapters 11, 18 and 19 of the Highway Capacity Manual (4.) The second approach is focused on evaluating the compatibility or suitability of bicycle travel along existing roads based on roadway conditions and traffic operation factors. This approach was deemed most applicable to evaluate the East Coast Greenway in South Carolina, and a number of studies centered on this approach are cited in the following paragraphs.
Sorton and Walsh (5) evaluated stress level for casual and experienced cyclists based on curb lane width, adjacent traffic volume, and adjacent traffic speed. Davis (6) used route data to compare various combinations of conditions affecting cyclist perception of exposure to traffic volume, traffic speed, lane width, grade, pavement condition and several other factors. Additional work on this aspect of cycling includes Landis (7) and Kahn (8.) Putman and Ross (9) used suitability analysis methods to evaluate 700 roadway segments in Madison, Wisconsin. The results demonstrated the application of suitability methods for use on a network basis.
200 participants evaluated video-recorded conditions for roadway locations in different cities and provided a value indicating their comfort level based on work by Hughes and Harkey (10) and Harkey et al., (11,12,13.) Physical measurements at each site were used in a regression analysis to determine a bicycle compatibility index. Factors used in the prediction formula included curb lane width, presence of bike lane, exposure to parking, motor vehicle speed, lane volumes, and type of developed area. This work provided the basis of The Bicycle Compatibility Index: A Level-of-Service Concept, Implementation Manual, FHWA-RD-98-095, (1.) This method was used to conduct route analysis along the 259-mile length of East Coast Greenway in coastal South Carolina. The BCI index was developed for urban and suburban roadway segments, however, no such method has been developed for similar rural roadway segments. Thus, the BCI analysis procedure was adapted for comparative evaluation of rural roadway segments.
Since the BCI method was established in 1998 additional research has been conducted to evaluate bicycling on rural routes by Jones and Carson (14) and Noel, et. al., (15.) The study conducted by Jones and Carson used a procedure developed to closely match the BCI methodology. It incorporates both geometric and operational variables considered important by adult bicyclists in terms of their comfort level when riding on rural roads in the presence of motor vehicle traffic. A web-based survey was used and the participants were asked to view numerous roadway segments captured on videotape and rate these segments with respect to how comfortable they would be cycling in the geometric and operational conditions shown. Results of the survey were analyzed using linear regression to create a rural bicycle compatibility index (RBCI) model. Noel, et. al., developed a procedure to evaluate rural segments in Quebec from a bicycle suitability point of view. This analysis placed particular emphasis on the cyclist’s perspective. A compatibility of roads for cyclist (CRC) method was developed using a survey with 200 cyclist participants. A panel of experts and officials decided to include the most important variables in the CRC model, as identified by the study participants. Unfortunately, these two procedures are not yet advanced through development efforts to the point of being widely applicable to other areas yet. Therefore, the FHWA BCI method focusing on urban and suburban was used for the SC ECG, and adapted for use on route segments exhibiting rural characteristics.
III. DATA COLLECTION
Roadway, traffic and land use data was collected on 72 sections, 234 segments and 1,615 sub-segments, delineated with respect to uniquely descriptive characteristics. This information was used as the basis for conducting an analysis of routes for the modified existing SC East Coast Greenway route. The method selected to evaluate individual segments was The Bicycle Compatibility Index, FHWA-RD-98-095 (1.) This study established a procedure for determining how roadway conditions and traffic operations impact a bicyclist's compatibility in traveling a specific section of roadway, under mixed traffic conditions (bicycles and motor vehicles.) The BCI methodology was developed with intention for use on urban and suburban road segments (mid-block locations, excluding intersections.) It incorporates an array of variables assessing the "bicycle friendliness" of a road and generally provides an indication of compatibility for other non-motorized modes likely to use the Greenway. The BCI method uses a multi-variable regression formula, which is documented in Appendix A, to calculate an index value linked with traditional Level of Service (LOS) designations, A through F, with A being the best conditions and F being the worst. BCI-LOS ranges are summarized with respect to bicycle compatibility levels in Table 2.
Table 2 – BCI Value, LOS & Compatibility Ranges
An extensive data collection and analysis effort was required to develop the robust database needed to evaluate routes and connections along the SC East Coast Greenway corridor. An overview of this process is graphically summarized in Figure 2. In addition, data sheets describing all route segments are provided in Appendix B. Each segment is represented as a line of data. The total database for the project includes 137 sections and 450 segments, with the modified existing route reflected in route maps and route tabulations, consisting of 72 sections and 234 segments. A flow chart schematic of the sections considered for the entire ECG corridor is provided in Figure 3. This diagram served as the central linkage between roadway data and geocoding, and furthermore, allowed comparison of the feasibility of possible alternative routes within the corridor. Road lengths for sections and segments were determined at the sub-segment level via GIS and are not included in the data sheets provided. As this method was developed for urban and suburban routes, several limitations and biases were noted and addressed through use of adjustments in the process. These issues are summarized as follows:
BCI Method Limitations
IV. ROUTE ANALYSIS USING BCI
The BCI analysis was applied to the modified existing ECG and its possible alternative routes within the predefined coastal corridor. Of specific interest from an analysis standpoint is the relationship between BCI ratings and major factors such as ADT volume. A plot of this relationship is presented in Figure 4. This plot is based on all 450 route segments contained within the Greenway corridor, and not merely the 234 segments of the existing route. It is evident that BCI rating, and correspondingly LOS, deteriorates in relative proportion with increased ADT. However, an unanticipated observation was identified within the data occurring along low-volume roads, as volume approaches “0,” the BCI rating remains relatively high, evidently being affected more significantly by motor vehicle speed than by traffic volume. This problem was addressed through adjustments to the BCI procedure, described in the following sections.
for BCI Adjustment on Low-Volume Roads
Basis for BCI Adjustment
Based on this background information and knowledge of traffic engineering flow parameters, a maximum threshold value of 2,500 vehicles per day was selected, for which lower ADT values were used to adjust the BCI rating downward to better reflect the actual favorable conditions for cycling on these low-volume roadway segments. This is considered to be a relatively conservative value, and as a result of keeping this threshold as low as possible, a fewer number of segments necessitate adjustment. A careful review of BCI adjusted road segments within the SC ECG corridor, verified that the perceived BCI-LOS rating more closely matched actual route conditions. However, it should be noted that additional analysis of the database, and possibly further data collection, need to be accomplished prior to applying this threshold value to other similar projects or studies.
Adjustment Procedure for Low-Volume Roads
of BCI Adjustment on Database
3 – Tabulation of Adjusted BCI Route Segments, N=89
Based on the route analysis process for the SC East Coast Greenway corridor presented in Chapter 2, a variety of tabulations describing the route were developed with respect to each of the three coastal planning areas. This information is presented in Tables 4 through 9. It should be noted that the overall route length of 259 miles is greater than the 240-mile length reported in East Coast Greenway planning documents. This total length was determined from a summation of specific GIS links. However, this value is slightly inflated due to the presence of one-way bridges on US 17 in the Charleston area over both the Ashley and Cooper Rivers. In essence, GIS tabulations count each direction separately which results in padding the overall route length to a minor degree. No adjustments were made to account for this since these actually are separate roads with unique geometric features and traffic conditions. Based on information contained in Tables 3-8, the following optimistic and pessimistic aggregations are noted.
Optimistic Route Tabulations
Pessimistic Route Tabulations
Table 4 – Route Tabulation of Bicycle Facilities
Table 5 – Route Tabulation of Sidewalks
Table 6 – Route Tabulation by Shoulder Type
Table 7 – Route Tabulation by Speed Limit
Table 8 – Route Tabulation by ADT volume
Table 9 – Route Tabulation by BCI/LOS Rating
The existing East Coast Greenway route is graphically represented for each of the three planning areas, Lowcountry, Charleston and Waccamaw) in Figures 6 through 8. It should be noted that slight modifications were made to route locations when higher volume roads along the currently planned Greenway paralleled low volume roads that were readily apparent as desirable alternate locations, prior to construction of off-road facilities. An example of this is in Charleston County, near the Town of Ravenel, where Old Jacksonboro Rd., a very low-volume 2-lane road, closely parallels US 17 for a distance justifying relocation of the Greenway route onto this more compatible low-volume, two-lane road segment. Also, existing locations of the route situated along unpaved roads were relocated for analysis purposes and evaluation consistency to nearby parallel paved routes. An example of this occurs in Jasper County, between Hardeeville and Switzerland, where the modified route was relocated for analysis purposes from Old Kings Hwy. to US 17.
Area overview maps are intended to show the general location of each area of the greenway. Details of specific routes, and possible Greenway alternatives, within each of the three coastal planning areas are presented in the following sections via larger scale maps and further discussion. The breakdown of route maps by planning region is as follows:
For the purpose of discussing specific route details, the SC East Coast Greenway is examined in a systematic order from south to north. As the Lowcountry Region is the southern most planning district linking the route to Savannah, Georgia, this area is presented first in the specific route evaluation. This portion of the greenway is being developed with a Revolutionary War theme, connecting a number of important historic sites including battlefields, forts, cemeteries and churches. As currently identified the route covers 76-miles through this region, and the modified existing ECG route is defined by 12 sections, 36 segments and 250 sub-segments. None of the route currently includes bike lanes or multi-use path facilities and only 2% (1.75 mi) contains an adjacent sidewalk. On a more positive note, 82% (63.01 miles) is located along low volume roads with traffic of 5,000 vehicles per day or less. Upon entering SC, the Greenway is routed inland to avoid heavily traveled roadways and problematic bridge crossings.
As shown by the map in Figure 9, the East Coast Greenway enters South Carolina from Hutchinson Island located directly across the river from the City of Savannah. It should be noted this particular configuration does not provide a landside linkage, but rather relies upon a water taxi service, which offers passage across the river. The Talmadge Memorial Bridge on US 17 allows direct access to Savannah for motor vehicles; however, the bridge currently exists as a limited access facility and prohibits non-motorized traffic. As the Greenway enters South Carolina on US 17, it crosses a bridge on the Back River that exhibits very low compatibility for bicycling, BCI-LOS E and index rating of 5.17. The route transitions from the Back River Bridge onto a section of US 17 with a 2-ft. shoulder, depicted in Figure 8. Conditions along this two-lane route segment are generally characterized by heavy traffic volume, high speeds, low compatibility for bicycling, and BCI-LOS E with a corresponding index rating of 4.92.
Once the route reaches SC 170 Alt., several alternative routes were analyzed. The existing route follows US 17 and up to a point where the route turns left onto Purrysburgh Rd. and later connects with Old Charleston Rd. (shown in Figure 10,) which is very compatible for bicycling, rated as BCI-LOS A with an index rating of 1.17. However, this route section currently contains long segments of unpaved roads, such as Old Kings Hwy., shown in Figure 11. Even though the BCI rating is favorable due to very low traffic volumes, touring cyclists are likely to encounter difficulty traversing lengthy unpaved segments such as this. Application of a fine-grain wearing-surface would go a long way towards improving these road segments for bicycling. For analytical purposes and evaluation consistency a slightly modified existing route was used instead to connect through Hardeeville along US 17.
Another slight modification of the existing route was made in the Town of Ridgeland where the route was moved from US 17 to Green St., a road that exhibits BCI-LOS B and has a very high compatibility with bicycling. The route extends north along I-95 frontage roads where it merges onto US 17 for a short distance in Point South, see the map in Figure 14. From there the route turns left onto McPhersonville Rd. and continues through the Town of Yemassee as it merges onto US 17 Alt. for several miles before turning right onto Ritter Rd. and then right again onto SC 64 connecting into the Town of Jacksonboro, see the map in Figure 15. Other than the portion on US 17, all are two-lane roadways, and except for US 17 and SC 64, these segments exhibit BCI-LOS C or better providing a moderately high compatibility for bicycling. Contrasting these favorable ratings to the parallel option of traveling much more treacherous sections of US 17 through Gardens Corners and then onto Jacksonboro, this route experiences a BCI-LOS of E for the entire length and the roadway is typified by heavy traffic volumes, considerable truck traffic and high motor vehicle speeds. Road conditions and corresponding analysis data for US 17 on a segment near the Combahee River is shown in Figure 11.
VII. Charleston Region – Route Analysis
Within the Charleston area the modified existing ECG route covers 98-miles and is defined by 27 sections, 85 segments and 588 sub-segments. A planning study is currently underway with the objective of creating a master plan for proposed facilities need to accommodate the Greenway in Charleston County and to integrate these future facilities within an overall long-range transportation plan. Transportation consultant, Kimley-Horn & Assoicates, is in the process of conducting this study, under direction of Berkeley-Charleston-Dorchester Council of Governments, funded through a SC State Forestry Commission grant.
The route enters Charleston County on US 17 at the Edisto River Bridge. This particular section is located along a high-speed, four-lane divided roadway with no shoulder. The BCI-LOS is E with a rating of 4.85. In its current configuration, this section has a very low compatibility for bicycling. As the route approaches Parkers Ferry, Old Jacksonboro Rd. begins to parallel US 17 and this road provides an excellent option to the somewhat treacherous road environment along US 17. Favorable conditions along Old Jacksonboro Rd. accommodate a BCI-LOS A with an index rating of 1.22. Therefore, most segments of Old Jacksonboro Rd. from Parkers Ferry through the Town of Ravenel were used as the existing modified ECG route for evaluation purposed and result tabulations, see the map in Figure 16.
Another option instead of using US 17, is for the route to extend along SC 174, SC 164 and SC 162. BCI-LOS ratings are generally more compatible, ranging from LOS B to D. However, all of the possible routes in this area merge back onto US 17 at Rantowles Creek where the conditions have an extremely low compatibility for bicycling with BCI-LOS F and index rating of 5.44. As this is a critical link along the Greenway route, with no alternative routes available except to move the interim route ten’s of miles inland, this section should receive a high priority. As a stopgap measure within the ECG improvement plans, provision of a paved shoulder would be very beneficial to Greenway users and motorists alike along this section of US 17, as well as the previously mentioned US 17 section near the Edisto River.
Once the route reaches the community of John’s Island, the Greenway is located along a converted rails-to-trail facility known as the West Ashley Greenway extending 7-miles into the City of Charleston, see Figure 17. This facility is unpaved but affords a welcome relief to a very poor heavily developed commercial suburban section of US 17 providing LOS F, with 6.01 BCI rating. The eastern terminus of the West Ashley Greenway occurs at an extremely busy section of Folly Beach Rd. where the route must cross amidst very complicated traffic patterns and connect to the Ashley River Bridges on US 17 which exhibit extremely low compatibility for bicycling of BCI-LOS F and a rating of 5.93, see Figure 18. Alternative routes considered in the evaluation for this area are presented in Figure 19.
Once the route crosses onto the City of Charleston’s downtown peninsula, conditions improve dramatically for bicycling along the existing Greenway route. Lockwood Dr. contains a 10-ft. wide multi-use path, shown in Figure 20. This facility extends through waterfront land uses along the Ashley River and unfortunately includes some very narrow sections, 5-ft. in width, further constrained via concrete barrier railings on both sides. At the end of Lockwood Dr., the route transitions onto low-volume neighborhood streets and then onto a parkway setting along Murray Blvd. shown in Figure 21. These type roadways accommodate a BCI-LOS of C or better, as currently configured, based mostly on low traffic volume and low motor vehicle speed. Due to the historic nature of this area and significant right-of way constraints, it is unlikely the Greenway will be further accommodated via physical facilities along these type routes. This should be of little concern as this residential area is already very pedestrian and non-motorized mode friendly, in its currently state.
After the route rounds the tip of the Charleston peninsula and heads up E. Battery St. and E. Bay St., adjacent land use becomes more commercial and industrial as it passes port and shipping terminal facilities. Currently, the Greenway is circuitously routed onto the existing Silas N. Pearman Cooper River Bridge, which has an extremely low compatibility for cycling with a BCI-LOS F and index rating of 7.63 (second worst rating of any segment along the Greenway in the State of SC.) Fortunately, this significantly deficient segment will be rectified within a year upon completion of the new Cooper River Bridge that will include a 12-ft. wide multi-use path extending between Charleston and Mt. Pleasant. On the Charleston side the path will connect to existing roadways at E. Bay St. and some facilities would be very useful to connect the Greenway with the Concord St. loop. Otherwise the Greenway may need to be routed on an interim basis along residential streets through an economically depressed neighborhood on Charleston’s east side, due to the fact that adjacent segments on E. Bay St. experience a BCI-LOS E with a rating of 4.92. These and other routes considered as part of the evaluation for downtown Charleston are shown on the map in Figure 22.
Heading further up the coast from Charleston, the Greenway passes through the Town of Mt. Pleasant and extends along the barrier island towns of Sullivan’s Island and Isle of Palms, before crossing back into Mt. Pleasant, see the map in Figure 23. After traversing the Cooper River Bridge, the route extends along Coleman Blvd., which contains some bike lanes as shown in Figure 24. As this section of the Greenway is located along a heavily traveled multi-lane road, the presence of a bike lane is very beneficial and improves the BCI-LOS from E to D, with an index rating improvement from 4.87 to 3.71.
After crossing scenic Shem Creek, the route passes through the Old Village of Mt. Pleasant. These residential streets are very compatible with bicycling and generally exhibit a BCI-LOS of C or better. The Greenway is then routed on a narrow, 5-ft. wide, multi-use path extending across the Ben Sawyer
causeway and connecting with the barrier island town of Sullivan’s Island. This facility accommodates a BCI-LOS of C with an index rating of 3.29. However, when the facility encounters a discontinuity in crossing the Intra-coastal Waterway movable-span bridge, the BCI-LOS decreases significantly, dropping to F with an index rating of 5.34, see Figure 25. Currently there are discussions of replacing this structure, however local residents are opposed to a high-level, fixed-span bridge and presently this impasse has slowed down development of improvement plans. Upon entering Sullivan’s Island, the route turns left onto Jasper Blvd., which intermittently contains bike lane segments and is highlighted by a beautiful new bridge extending across Breech Inlet that includes wide shoulders, 5-ft. wide bike lanes, ample sidewalk width and provides a sweeping view of the Atlantic Ocean. Once on the Isle of Palms, the Greenway contains a bike lane on one side (southbound direction) only. The route then turns left on the Isle of Palms connector, a 3-lane bridge that extends for 3-miles across tidal marsh. Even though this roadway experiences a BCI-LOS D with index rating of 3.94, the presence of 10-ft. shoulders on both sides provides conditions that are favorably perceived by the public and, correspondingly, the facility is frequently used by runners and cyclists alike. Due to increasing traffic congestion in this area, pressures are emerging from the highway and development communities to re-stripe the bridge to accommodate two-lanes in each direction, thus significantly reducing the current buffers used by non-motorized modes and correspondingly adversely affecting the BCI-LOS rating.
The Greenway route then extends along Rifle Range Rd. and Porches Bluff Rd. until merging with US 17. The route extends along US 17 for several miles under poor conditions of heavy traffic and high speeds, which exhibit extremely low compatibility for bicycling with a BCI-LOS F and index rating of 5.36. Once the route reaches the rural township of Awendaw, route parallel options are available for approximately 13-miles along adjacent low-volume, two-lane roads including Sewee Rd. and Doar Rd., which accommodate BCI-LOS of C and A respectively. Conditions on these roads are considered so favorable for cycling that local bicyclists frequently use these roads on club rides. The route then merges once again with US 17 for a long section extending all the way to the Santee River delta where the route crosses into Georgetown County. Portions of US 17 contain a narrow 2-ft. shoulder and this improves the BCI-LOS from E without a shoulder, to D with a paved shoulder.
It is worth noting that other parallel roads extending through the Francis Marion National Forest along Halfway Creek Rd. and passing by the Santee Coastal Reserve were also considered in the route analysis. Initially these roads appeared to be strong candidates for relocating the Greenway route away from heavily traveled, high-speed segments on US 17. However, since alternative parallel routes in this area all include lengthy segments on unpaved roads, typically consisting of soft sand, these routes were deemed unsuitable without provision of bicycle friendly pavement surface-course. Touring cyclists and other non-motorized modes using the East Coast Greenway would likely experience difficulty in negotiating conditions such as these. However, if pavement conditions were improved on these roads, the opportunity of avoiding poor conditions on US 17, while connecting with major points of interest such as Hampton Plantation or the fishing village of McClellanville, would render the possible use of these alternatives very advantageous. Regardless, these facilities are likely to take sometime to develop and it has been presumed that in the meantime the route would need to use roads with more durable pavement surfaces. Routes considered as part of the Greenway evaluation for the Awendaw and McClellanville area of eastern Charleston County are depicted on the map in Figure 26.
VI. Waccammaw Region – Route Analysis
Within the Waccammaw Region the modified existing ECG route covers 85-miles and is defined by 33 sections, 113 segments and 777 sub-segments. A recently completed planning study created a master plan for proposed facilities needed to accommodate the Greenway in Georgetown and Horry Counties. Planning consultant, Haden Stanzaile, conducted the study under direction of Waccamaw Regional Planning and Development Council funded through a SC State Forestry Commission grant.
The route enters Georgetown County on US 17 at the Santee River delta bridges. This particular section is located along a high-speed, four-lane divided roadway with no shoulder. The BCI-LOS is E with an index rating of 4.44. As it currently exists, this section has a very low compatibility for bicycling. The Greenway is diverted onto a scenic low-volume, two-lane loop in route to Georgetown via N. Santee River Rd, Estherville Rd. and South Island Rd. The BCI-LOS along these routes is generally C, and road conditions exhibit moderately high compatibility for bicycling. Routes considered as part of the evaluation for southern portions of Georgetown County are shown on the map in Figure 27.
The Greenway route merges with US 17 just prior to crossing the Sampit River Bridge, which has 6-ft. shoulders and provides a moderately compatible BCI-LOS C. Upon entering Georgetown proper, the Greenway is routed onto low-volume residential streets including Kaminski St., Front St., Cleveland St., High Market St. and St. James St., prior to merging back on US 17 on the north side of town. All of these roadways exhibit a BCI-LOS of C or better, see the map in Figure 28 for roads included in the evaluation. Leaving Georgetown on US 17, the route immediately crosses the Great Pee Dee/Waccamaw River Bridge where heavy traffic volume and high travel speeds produce a BCI-LOS E with corresponding index rating of 5.10, indicating conditions of very low compatibility for bicycling, see Figure 29.
From the bridge north to Pawleys Island, US 17 contains a narrow 2-ft. wide paved shoulder, however open road conditions lead to a BCI-LOS E and index of 4.56. Fortunately, several developers of large tracts of land on the east side of US 17 are interested in incorporating the Greenway route into their development plans, moving the facility comfortably away from this busy high-speed section of US 17. A mile or so prior to entering Pawleys Island, Kings River Rd. provides a parallel option to a relatively long stretch of US 17 extending into Litchfield Beach. This facility is a two-lane low-volume road traversing through expansive residential areas and generally providing a BCI-LOS C, see Figure 30.
Other routes through Pawleys Island considered in the evaluation included Myrtle Ave., Waverly Rd., Library Ln., Petigru Dr. and Parkersville Rd. These routes are identified on the map in Figure 31. It is interesting to note that a short section on US 17 between S. Causeway Rd. and N. Causeway Rd. in Pawleys Island already includes a multi-use path allowing this busy commercialized roadway to accommodate a BCI-LOS C. However, this facility is not frequently used by pedestrians or bicyclists and is generally perceived by local residents as uninviting. Based on this experience, if multi-use paths are planned and constructed within the existing right-of-way along US 17, careful attention to design detail
will need to be created to ensure a higher type facility is provided. Inclusion of an adequate and aesthetic buffer between the multi-use path and motor vehicle travel lanes, as well as spacing and treatment of driveway crossings, are important issues to address within the context of creating a successful design.
Kings River Rd. connects with an 8-ft. wide multi-use path located in the Wilbrook Blvd. right-of-way providing a BCI-LOS B, as shown in Figure 32. This facility links to a 6-ft. wide multi-use path located along US 17 extending from Litchfield to N. Litchfield, as depicted in Figure 33. Due to heavy traffic volumes, fairly high motor vehicle speeds, frequent driveways and relatively narrow width, the US 17 multi-use path falls to BCI-LOS C. However, once this path ends traveling north on US 17, at Huntington Beach State Park, the BCI-LOS worsens to E with a rating index of 4.93, even though a narrow 2-ft. paved shoulder is present. Preliminary details for an off-road path are currently being negotiated with State Park officials that would move the Greenway away from US 17 travel lanes.
The Greenway then passes through the seaside towns of Murrells Inlet, Garden City and Surfside Beach and is able to use connecting roads and streets to form a parallel alternative route to the major traffic handling facilities of US 17 and US 17 Bus., see the map in Figure 34. In the Town of Murrells Inlet, the route diverges from US 17 and follows US 17 Bus. where a 5-ft. wide bike lane is provided, see Figure 35. The route briefly converges along a major section of US 17 Bus. and then diverges onto an accommodating loop via Atlantic Ave., Ocean Blvd. and 17th Ave. A BCI-LOS C is generally provided along these routes, which exhibits moderately high compatibility for bicycling. The Greenway route merges back on US 17 and initially is able to use a short portion of frontage road. Upon merging once again with US 17 Bus., the BCI-LOS immediately deteriorates to E with an index rating of 5.05, which provides a very low compatibility for bicycling.
Once in Myrtle Beach, the route heads inland circumventing the airport to a point where the Greenway connects with a long section of multi-use path located along Old Socastee Hwy. and Grissom Pkwy., see map in Figure 36. A 10-ft. multi-use path provides a BCI-LOS C with an index rating of 2.38, located within the right-of-way of a 5-lane arterial roadway, see Figure 37 (on previous page.) Even though it is possible to traverse towards the beach picking up portions of N. Ocean Blvd., an undesirable transition back onto US 17 Bus/US 17 is inevitable due to the fact that a proposed off-road facility paralleling Carolina Bays Pkwy. is not yet complete. This requires the Greenway to use a heavily traveled 6/8 lane major urban arterial exhibiting the worst BCI-LOS F rating index (7.73) in the State of SC. BCI-LOS F conditions are present along this section all the way to N. Myrtle Beach, where the route diverts onto S. Ocean Blvd. via S. 48th St. and the BCI-LOS drops to a more desirable level of C, see Figure 38.
Based on the diligent efforts of local planning officials, proposed plans are well underway to extend the Greenway along a multi-use path in the right-of-way of the newly constructed, limited access, Carolina Bays Pkwy. and within an adjacent section that will meander on a separate alignment though the Lewis Ocean Bay Heritage Preserve. Additional details have been coordinated to extend the Greenway across the Intra-coastal Water way and link to existing multi-use path improvements on Grissom Pkwy. The northern section of the Greenway will link with existing path improvements recently constructed along new development roads within the Barefoot Landing Resort. This path system extends towards the beach, connecting across the Intracoastal Waterway and US 17 ultimately linking with a previously described section of the Greenway on S. Ocean Blvd. This proposed facility constitutes a crucial link in the route joining considerable portions of the Greenway that are already physically established via multi-use paths, bike lanes and related proposed facility improvements located within the cities of Myrtle Beach and N. Myrtle Beach. In addition, the Carolina Bays Pkwy. linkage would have the significant added advantage of allowing the route to circumvent and avoid the worst BCI-LOS rated road sections, along US 17, in the State of SC.
Future plans to extend the Greenway along proposed beachfront development tracts within the Town of Atlantic Beach and, as a result connecting a missing link between adjacent segments of S. Ocean Blvd., appears to be a realistic possibility. However, timing of redevelopment initiatives within Atlantic Beach is yet to be determined, therefore the schedule of providing this desirable Greenway connection is unknown. Ultimately, this linkage will negate the need to detour along the route to the inland side of US 17 for a short 6-block distance, see location map provided in Figure 39.
Once in N. Myrtle Beach, the Greenway is oriented along an alignment that avoids US 17, via S. 48th St., S. Ocean Blvd., 33rd St., Wiley Dr., 27th St., S. Ocean Blvd. and SC 9. The BCI-LOS along these routes is generally C or D. Aesthetic promenade improvements are currently being considered for S. Ocean Blvd., as well as pavement re-striping, to provide more space for non-motorized travel modes along this beachfront roadway. Either of these improvement strategies would further enhance both bicycling compatibility and pedestrian suitability on this segment of the Greenway. In addition, Hillside Dr. parallels S. Ocean Blvd. and contains, along a considerable portion of its length, a narrow 2-ft. bike lane that provides a BCI-LOS A, with corresponding index rating of 1.43, see Figure 40.
At the northern end of N. Myrtle Beach, in the Cherry Hill area, the Greenway transitions onto a 5-lane section of the Sea to Mountain Hwy., SC 9. Due to heavy traffic volumes, this road exhibits BCI-LOS E conditions with an average index rating of 4.7 on this section, providing a very low compatibility for bicycling. SC 9 crosses US 17 and the Intra-coastal Waterway, after which the Greenway route uses local streets before merging with SC 90 and then transitioning onto a busy section of US 17 that extends into the Town of Little River, see Figure 41. This segment of US 17 exhibits conditions that have an extremely low compatibility for bicycles with a BCI-LOS F and a corresponding index rating of 5.84.
Once in the town of Little River, the Greenway is routed onto local low-volume two-lane streets passing through residential areas offering BCI-LOS A. Unfortunately the route merges once again with US 17 for a short distance where the BCI-LOS deteriorates to F, with corresponding index rating of 6.19. Once the route turns onto SC 179, a two-lane road, and connects with a signed bike route at the NC State line, the BCI-LOS improves slightly to E with an index rating of 4.70. This concludes the East Coast Greenway route in the state covering 259-miles in length extending through cities, towns, barrier islands, rural communities and pristine environs of coastal South Carolina.
VII. Findings and Recommendations
Data and descriptions contained in this report represent conditions of the East Coast Greenway route and corridor during the summer of 2003. Obviously progress has been made in various locations along the route since data collection efforts were completed, and some minor inconsistencies may be evident in the database used for this study. These negligible differences do not have an effect on the overall results of the study, which are intended to be a mirror of greenway route conditions at that time. The primary purpose of this study is to provide a resource to greenway supporters, agencies, advocates and decision makers, and to facilitate further development of the route. Specific details pertaining to master planning, route development and facility design are beyond the scope of this effort, and need to be addressed in separate more detailed studies. In is important to note that portions of the route are likely to exist under interim conditions for considerable periods of time into the future and reliance on linkages with the current road systems is inevitable. This study is intended to provide a better overall understanding of road linkages, a list of good routes that may suffice to accommodate the greenway as-is for many years to come, and identification of roadway sections that need timely attention to create a reasonable, functional and continual connection across the three coastal regions of the state of SC. Specific findings and recommendations are presented in the following sections.
Best Route Sections
Worst Route Sections
10– Best Route Segments Along Greenway
11 – Worst Route Segments Along Greenway
and Comparative Evaluation
Even though the goal of the East Coast Greenway Alliance is for the route to consist of 80% off road facilities, some route segments are likely to be acceptable as-is, from a functional standpoint, for the time being, allowing limited funding resources to be focused on portions of the route with the most need. Furthermore, differences between constructing a multi-use path within the right of way of a major roadway such as US 17 versus use of a parallel low-volume route that could not accommodate as extensive greenway improvements can be evaluated and reviewed on a case-by-case basis. Examples of locations where this type comparative approach would be useful include; Green St. in Ridgeland, Doar Rd./Sewee Rd. in Awendaw, and Kings River Rd. in Georgetown Co.
The importance of providing a durable and uniform surface course treatment for multi-use paths is a paramount consideration in creating a usable facility. Minimum pavement thickness for paths is typically recommended to be 7 to 15 cm (3 to 6 in.) for asphalt and 4 to 5 cm (1.5 to 2 in.) for concrete, assuming proper sub-grades and base courses have been constructed (21, 22). These depths are generally based on the minimum lifts at which paving materials can be constructed using conventional means. To provide longer durability, lower maintenance subsequent costs and address the contingency that additional loading may occur through non-design vehicle use, it is recommended that these minimum dimensions be increased and that special attention be given to base and sub-base materials. With regard to asphalt pavements, design criteria for use of high asphalt content to reduce thermal cracking as in low volume road appears most appropriate for bicycle path design.
Multiple Route Branches within Greenway Corridor
Differing User Types
Greenway User Input
Further Improvements to BCI Methodology