It's time for state to study possible carpool lane dangers

Published Monday, June 27, 2005, in the San Jose Mercury News

By Gary Richards

Q Changing lanes between the carpool lane and the normal lane can be a
really hairy experience.

Wallace Gardner
San Jose

A You and I know it, now ...


Q A recent Texas Transportation Institute study shows injury accidents
increased 41 percent to 56 percent for the most common type of carpool
lane (no physical barrier separation from regular lanes). Worse,
accidents jumped as much as 188 percent in the regular lane closest to
the carpool lane. The federal government has coerced states into
building carpool lanes for decades. Isn't this another example of the
law of unintended consequences?

Richard Diamond
Alexandria, Va.

A Could be ...

Q I know you're big on safety on the freeways as well as very
pro-carpool lanes, so I'd like to hear what you have to say about this
Texas study.

Joel Bratman
Sunnyvale

A I'd say it's time for a thorough study in California. The data is
alarming, but runs counter to a California analysis of carpool use on
Highway 101 in Santa Clara County a decade ago.

There are a couple of factors that should be noted, however. Texas
has converted some shoulders into carpool lanes, and the loss of a
shoulder can lead to a higher rate of crashes. In California, most
highways with carpool lanes have a shoulder. Also, to squeeze carpool
lanes into the median, Texas has narrowed some lanes from the standard
12 feet to 11 feet. That's usually not the case here. A good road to
study would be Highway 87 or Interstate 880, where carpool lanes are
in place or being added.


Q This concerns the carpool lane. Why should I move over and give up
my right with passengers to use that lane just because others want to
drive over the speed limit? I drive either 65 mph when no one is
behind me, or else slightly faster when someone is behind me.
Tailgaters continue to tailgate even when I increase my speed.

Nancy Hudson
San Jose

A I've said this before and I'll say it again. During carpool hours,
it is dangerous to be traveling faster than 65 mph in the diamond
lane, as traffic in the adjacent lane is usually going 20 to 30 mph
slower. Tailgaters, back off; enjoy the ride.


Q I believe I have noticed a shift in your attitude toward carpool
lanes. During the 1990s, you tirelessly championed carpool lanes.
While I hated sitting in the regular lane watching carpoolers zoom
ahead, I couldn't argue with your logic, and queuing theory -- the
study of how people wait in traffic or other lines -- certainly
supported you.

John Hart
Saratoga

A Who could argue with Mr. Roadshow?


Q Then in the late '90s, you began to argue that it was OK for soccer
moms or dads with kids to be in the carpool lane because there were
two or more people in the car and it would be too hard to enforce a
"two or more licensed drivers" law. Your position was probably
neutral to queuing theory because unlicensed drivers wouldn't add
extra cars to the road.

John Hart

A Yep, because some of those kidpoolers might indeed be taking a car
off the road, hauling around the kids of other parents (I was one of
those, once). And it would be a nightmare to enforce a ban on kids
counting for carpool-lane purposes.


Q Now you seem to be supporting single-occupancy hybrids moving to the
carpool lane, which means they will quickly be filled with hybrids
sitting still with everyone else during rush hour. That darn queuing
theory again.

John Hart

A Whoa. I'm the one who has been raising questions about the wisdom
of allowing hybrids into California carpool lanes based on what has
happened in Virginia. That's the only state that now permits solo
drivers in hybrids to use diamond lanes, and those lanes are filling
up. Virginia's law expires July 1, 2006, and that state has no plans
to extend it. Hybrids won't be allowed into California carpool lanes
until a new federal transportation bill is approved, which could
happen later this year. Caltrans can limit the total number of hybrids
allowed in carpool lanes to 75,000 statewide, so we have perhaps a
better plan. But what if those 75,000 are all on 101?


Contact Gary Richards at mrroadshow@... or (408) 920-5335