The last runaway truck ramp on westbound Interstate 70 before Silverthorne was used four times in the past month. That probably means four terrible wrecks were avoided. In the 1970s, trucks would burn up their brakes as they descended from the Eisenhower Tunnel to the curve before Silverthorne, often ending in tragedy.
The lower Straight Creek I-70 ramp is the most frequently used of six along the highway’s mountain corridor. Together, these ramps are used 60 to 70 times each year.
They also include upper Straight Creek — on westbound I-70 not long after the tunnel exit — two on westbound Vail Pass, on eastbound I-70 in Mount Vernon Canyon near Denver. Another ramp is on westbound U.S. 6 below Arapahoe Basin Ski Area; large trucks use this ramp when the I-70 tunnels are closed, or if they’re carrying hazardous materials.
The ramps are designed to stop a semi truck weighing up to 80,000 pounds and traveling at 100 mph, said a spokesman with the Colorado Department of Transportation. The number of trucks losing their brakes has also lessened over the past 30 years, with the use of automatic slack adjusters that help keep the brakes functioning properly.
Many truckers using the ramps these days may be accustomed to similar grades, but they aren’t prepared for the length of the incline. Others may be driving large rental trucks for their first time.
Most of Colorado’s runaway truck ramps were installed in the late 1970s to early 1980s. They are typically less than 2,000 feet long, but some run up to a mile. They include rounded crush rock varying in depth from 2 feet to 4 feet, according to a CDOT flier.
Because of restrictive terrain, no more ramps are planned along I-70 west. But a project is under way to improve truck safety from the tunnel to Silverthorne. It includes more truck warning signs, upgraded “Weigh in Motion” devices in the tunnel and revised speed limits. Improved pavement markings and delineation are also planned.
Runaway truck ramps are more frequently used in summer than winter, and non-commercial motorists need to be aware of the hazard. If you see a semi truck emitting smoke, move out of the way to allow access to the ramps.