Q.In other states, I see a lot of compact interchanges, often called “Florida cloverleafs.” They take up less land than a traditional interchange and move traffic roughly 25 percent better than California's typical four-way highway interchanges.
From personal experience, I can testify that this design makes for a much faster, smoother and easier flow thru the intersection.
For example, it only takes three light changes to service all four directions of flow rather than the four changes required by the standard layout.
I would like to know why Caltrans isn't more aggressive in adopting such a successful design. I understand the land isn't always available, and I know they tend to cost a bit more, but the payback in traffic flow efficiency is tremendous.
– Larry Shreve,Yorba Linda
A.Great question, Larry.
Cloverleaf designs are used in a few spots here in California where traffic is low, simply because that's where they work best, said Caltrans spokeswoman Yvonne Washington.
For those who are unfamiliar with cloverleafs, traffic entering from a looping onramp must compete in the same lane with traffic that uses the same ramp to exit the freeway, creating a condition known as weaving – similar to what we see at the I-405 interchange with Brookhurst Street in Fountain Valley.
When there are more vehicles on the ramp, the weaving worsens to the point that a full cloverleaf simply isn't practical, Washington said.
In more recent freeway designs, Caltrans uses a modified design known as partial cloverleafs, like the I-5 and Harbor Boulevard interchange in Anaheim.
Partial cloverleafs, Washington said, uses less land and alleviate most – but not all – of the problems created by weaving.
Q.Why are the streets near the border of Anaheim and Placentia so bad? It seems like the streets are worse after any improvement projects are completed.
Some of the potholes around Orangethorpe Avenue and Kraemer Boulevard have been filled, but there are still some rough patches.
The area along Orangethorpe, from State College Boulevard to Rose Drive, is the same way. So is Placentia Avenue, between Orangethorpe and State College.
Any time I drive these areas, I think I have a flat tire.