West Central Over-Height Vehicle Detection
The West Central Avenue railway overpass has been subject of multiple strikes by vehicles too tall for the 12-foot 7-inch clearance. Plaques posted on both sides of the bridge are supplemented by 13 advance warning signs (six from the east and seven from the west) on Central Avenue. All of the signs include flashing beacons or LED lights. Even with all the signage, drivers continued to ignore the warnings and drive into the bridge. Many impacts resulted in significant vehicle damage, as well as thousands of dollars in costs for the city to manage debris cleanup and traffic control, plus hours of travel delay and inconvenience for neighbors and residents. Staff considered lowering the pavement below the bridge to provide more clearance. Reconstructing several hundred feet of Central Avenue on either side of the bridge, as well as multiple residential and commercial driveways, upgrades to storm sewers, and obtaining permission from CSX Railway to excavate below their structure put the projected cost at about $1 million. A second alternative developed in 2015 involved the installation of a laser-activated advance warning system that would only activate for vehicles exceeding the posted height restriction. Studies show that motorists are more likely to obey a traffic control device that abruptly turns on verses one that continuously operates. A request for state safety funding prepared by City staff was approved in 2015.
The improvements included installation in 2018 of two large overhead flashing message boards that activate upon an over-height vehicle disrupting laser detectors located 1,000 feet ahead of the bridge. Communication between the laser controls and overhead message boards is by radio. The laser equipment is powered through 120 VAC connections while the overhead signs are solar powered. Notification is sent to the City Traffic Engineer by email with each activation. The planned addition of cameras will allow the notifications to be sent to the Police Department, and for the recording of video footage to provide information regarding the type of vehicles that activate the system and how the operator behavior changes when the sign comes on. Not all vehicles that activate the system necessarily strike the bridge as the vertical clearance for each depends on the overall vehicle length.
The new signage has reduced the number of bridge strikes and their severity. In 2019, the overhead detection device’s first full year of operation, there were four bridge strikes, compared to nine in 2018. Of those four, none required calling out city staff to assist in clean-up of truck or cargo debris.
Bridge Strike History Per Year:
Local Funding: $0
State Safety Program: $165,000