Inside Seven
Current Issue: September 2014
The McClure Tunnel leading onto Pacific Coast Highway is one of 21 tunnels cleaned last month in District 7.

by  Judy Gish
Issue Date: 05/2007

A clean tunnel provides better visability to motorists. Thanks, tunnel crew!

The tunnels of District 7 are definitely ready for their close-up.

Following a recent four-week effort, 21 tunnels are spic and span, thanks to the work of a specially-dedicated crew on loan from District 4. The cleaning was performed seven days a week because traffic restrictions required that they only work at night.

The crew uses equipment specifically designed for this purpose: a truck with a five-foot- tall articulated arm that spins at high speed against a tunnel wall while spraying hot, soapy water. This vehicle is followed by a large tanker truck of rinse water.

Measures to ensure the water does not escape into drains are scrupulously followed. Before the operation begins, the tunnels are sealed off at the entrance and exit. A huge vacuum at one end sucks up all the water. “The equipment is pretty cool,” says Maintenance Deputy Dan Freeman. “It moves about as fast as you can walk.”

The tunnels were last cleaned in 2001, Freeman said, adding that the benefits of the operation weren’t just aesthetic but also enhanced safety; Clean tunnels are brighter, improving visibility. Roughly estimating the cost at between $150,000 and $200,000, Freeman said he would liked to see the cleaning take place more often and could envision every other year, depending on the availability of the crew and other resources.


A suction device attached to a tanker truck vacuums up dirty water to protect storm drains during the cleaning process. An articulated arm spins against the tunnel walls as the truck it is attached to drives slowly through the area. The articulated arm in detail. A tanker truck spraying clean water follows the cleaning vehicle.