Weather Sensors Keep Bridges and Tunnels Safe

When Mother Nature kicks up her heels with high winds as she did recently, MTA Bridges and Tunnels uses a system of technologically-advanced weather sensors to help keep motorists safe.

The road and weather information systems used at all seven MTA bridges include above-ground atmospheric sensors that deliver highly- accurate weather information, including wind velocity, wind direction, humidity and precipitation, via wireless communication. Based on the data collected, actions are taken ranging from lowering speed limits, banning certain vehicles from crossing to sending out trucks to spread salt.

The small, rocket-like weather sensors attached to light poles often go unnoticed by motorists as they cross the spans, yet they are constantly recording data, including wind speed, velocity, direction and sustained wind times. They also measure rain and snow.

The system has been in place since the early 1990s but the latest upgrade, completed in 2008, includes cutting-edge technology which results in information virtually being received in real time.

Though traffic delays may occur when restrictions are put in place, "These procedures are designed and implemented to insure the safety of our customers," said Chief of Special Operations James Fortunato.

The information is sent to facility managers to be used as a guideline to determine whether restrictions are necessary. It is also used to dispatch maintenance crews to stand by in the event that emergencies develop as a result of extreme weather conditions.

Phase I speed restrictions are implemented when winds reach between 40 mph to 49 mph in dry conditions, or 30 mph to 49 mph when roadways are wet or icy. Other factors, such as wind direction, are also considered in making this determination. Speed restrictions are then relayed to motorists via electronic signs and stationary flip-board signs.

Along with a reduction in speed, Phase II restrictions bar certain vehicles, including tractor trailers, motorcycles, step vans, motor homes and mini-buses, from crossing the bridges. These restrictions are not common.

Phase I restrictions were put in place 16 times between January and November in 2009, while Phase II restrictions were put in place only once.MTA Bridges and Tunnels two tunnels --- the Queens Midtown and Brooklyn-Battery Tunnel -- have slightly different weather systems in place since they are not exposed to the same wind conditions as the bridges.