(November 10, 2009) Travel along MD 135 (Maryland Highway) down Backbone Mountain in Bloomington ends with a 90 degree right turn, which can be difficult to navigate, at a high rate of speed. In recent years the Maryland State Highway Administration (SHA) has enhanced safety by adding three mandatory truck pull off areas requiring truck drivers to stop and verify their brakes are functioning properly. SHA also lowered the speed limit for commercial trucks to 10 mph.
Crews dig out truck following successful use of runaway truck ramp traveling down Backbone Mountain on MD 135.
In November 2007, SHA installed a runaway truck warning system at the top of the downward side of MD 135. The warning system detects the length and speed of a truck as it passes underneath an overhead sensor. In addition to the warning system approximately 25 signs were upgraded with brighter colors along the road with varying messages about the grade length, grade speed, truck escape ramps, brake check pull off locations, etc.
SHA’s runaway warning system was put to the test for the first time in March 2008 when it was activated by a 77, 500 lb. tractor trailer. The driver Gregory Gibson said he had never been west of Frederick and had no knowledge of the downgrade along MD 135. Gibson saw the flashing lights on the runaway warning sign activate as he approached and when his engine began to race he knew his brakes would not stop the truck. He then proceeded to the runaway ramp, by the time he reached the ramp the vehicle was traveling at such a high rate of speed that it ascended 705 feet up the ramp through a deep bed of pea gravel.
Tow truck removes truck from a deep bed of pea gravel used to slow down vehicles on escape ramps.
On Monday, November 9th, the truck warning system was put to the test again - saving another life. A truck weighing approximately 78,000 lbs. experienced transmission failure and loss of brakes, the driver used the runaway truck ramp on MD 135 to stop the vehicle. The truck entered the ramp traveling between 45-50 mph, the vehicle traveled 550 feet up ramp before coming to a stop in a bed of pea gravel.