Practice Details
State Agency: Vermont
Practice Provision: Use of safety intrusion alarms in work zones
Description:
After testing two models of the work zone intrusion alarm, Vermont DOT's research unit purchased a model that uses an infrared beam sent from a transmitter unit to a receiver unit that also houses the siren. When a vehicle breaks this beam, the siren goes off. The research unit picked this model because it was the fastest and easiest to set up.
The work zone intrusion alarm's first application in Vermont was in early 1995, when a bridge deck condition survey closed one of the bridge's two lanes to traffic. When vehicles tripped the alarm, the siren was more than loud enough to be heard over the generator and other equipment at the work site. Since then, the research unit has used the intrusion alarm at nearly a half-dozen work zones.
Assessment: The intrusion alarm is best suited for certain projects, according to Allan Schneck of Vermont AOT. "When we have day-long or shorter projects, this equipment is very useful," he says. Because the research unit sends out very small teams, he explains, it is hard to justify sending out a flagger to provide work site safety, especially when the crew will be at the site only for a few hours.
The intrusion alarm still needs some fine-tuning, Schneck says-even regular users have trouble getting it set up properly at job sites that lack shoulders wide enough to place the two parts of the intrusion alarm.
Despite the intrusion alarm's need for a few adjustments, Schneck likes the device and is encouraging other units in the State highway administration to try it at projects. "I think with some more information and experience, people will develop more interest in the alarm," he says. "The device does have merit."
The intrusion alarm will prove its value the first time it prevents injury to highway workers, Schneck predicts. "We haven't had any near misses, but I expect that just one would more than pay for the $3,000 cost of the alarm system."
Where Documented: Case study titled "Alarm System Improves Safety in Work Zones"
