Amount of rubber exposure in asphalt mix is minuscule
Q
While I am happy to hear about recycling old tires for paving, my concern is that particles of rubber dust released into the air from constant driving pressure could cause cancer. There was an article in a health magazine on whether artificial turf with ground-up rubber particles to mimic dirt was causing cancer to soccer players. Any comments? — Leigh Oakley, Carlsbad
A
These issues have been studied for many years, and the two situations are not comparable, say the Roadshow science experts. Asphalt pavement is about 95 percent crushed stone and sand, with the remaining 5 percent liquid heated to bind it together. The asphalt contains recycled rubber that only replaces some of that binder.
Once the asphalt mix is placed into the ground, compacted and then is cool enough to accommodate traffic, the rubber exposure is minuscule to the point of being almost nonexistent.
Q
Will Caltrans install rubberized asphalt on the paving job on Highway 92? — Mary Lee, Redwood City
A
No. To use rubberized asphalt, Caltrans needs warmer nighttime weather. Temperatures along this mountain highway to the coast are too chilly at night. Work on the $4.2 million four-month paving project from Interstate 280 in Belmont to Pilarcitos Creek Road at the eastern edge of Half Moon Bay is scheduled Sunday through Thursday between 9 p.m. and 5 a.m. with one-way traffic controls.
Q
While driving up Highway 101 in south San Jose the other morning and admiring the freshly painted lane stripes, I could see that all the white dashes in the slow lane were not paint but long plastic strips glued to the pavement. Is this an experiment? It’s amazing the detail you notice at 10 mph. — Dennis Cole, San Martin
A
More than an experiment. It’s the way Caltrans lines our highways these days, increasing the size of the striping from 4 to 6 inches. It makes it easier for drivers, especially older folks, to see and are far less likely to come loose as Botts’ dots did.
Q
Who is responsible for the traffic lights on Highway 84/Bayfront Expressway? I have no way to count how many hours I’ve lost in recent months because of traffic lights flashing 4-way red at Chilco Street during morning rush hour, or ill-programmed sensors at Chrysler Drive, etc.
While they’re at it, can Menlo Park Police Department dedicate some resources to ticketing drivers (especially bus drivers) running red lights and blocking the box trying to get into Facebook? — Greg Heibel
A
The signal controller at Chilco will be replaced. As for the light at Chrysler, there’s been a lot of construction in the area and it has affected the light. Changes to the signal will come when the nearby construction wraps up.
Menlo Park cops have been told of the red-light runners.