Meet the Road Monitor
New Hampshire's Department of Transportation, in conjunction with Plymouth State University, is about to tackle a particularly thorny problem: unpredictable road surface conditions. The Road Weather Information System (RWIS) consists of multiple sensors and towers that report local conditions to the DOT and other agencies. Let's take a closer look.
Stephanie vL Henkel
Temperature probes buried ~47 cm below the roadway surface and hardwired to the surface sensors will help determine frost depth. The surface detectors (Surface Systems Inc., www.ssiweather.com), resembling hockey pucks, will be embedded in the pavement. These will detect and relay specific road conditions such as dry, damp, wet, or snow/ice-covered, and pavement temperature, as well as whether an anti-icing chemical has been applied to the surface. They will communicate their data wirelessly to a nearby tower, as will others in the suite of sensors at each location: ambient air temperature, relative humidity/dew point, visibility, wind speed and direction, ozone levels, and type and rate of precipitation. At some sites, traffic monitors will be installed to provide vehicle counts, speeds, and classifications.
Equipped with additional sensors
All 11 RWIS sites will be polled at 20-min. intervals. A central server at the DOT headquarters in Concord will allow simultaneous polling. Broadband connections will be used wherever they currently exist, and dial-up modems will do the job elsewhere. The real-time information will be invaluable for making decisions about when and how to treat a stretch of highway; identifying dangerous patches so that traveler advisories can be issued; and forecasting pavement conditions for specific roadway segments. The meteorological data will also be shared with other government agencies and with educational institutions.
Pavement sensors report their data to nearby towers
The project is funded by the NHDOT, FHWA, and NOAA. To read "Implementation of RWIS in New Hampshire," visit http://tinyurl.com/m9u4n
Progress in Reverse
This is an unusual item for the R&D department, but there was simply no other space for it in this issue. And we think the technology is important enough to warrant a deviation from our standard fare. In a nutshell, radar-based object detection has been linked to a brake interlock system to yield a new system that not only alerts a truck driver to something behind the rig, but actually stops the vehicle before it strikes or runs over that object.
The brake system components
This is the result of technology sharing between MICO, a manufacturer of hydraulic brakes, and Preco Electronics Inc. (www.preco.com), a maker of vehicle communication systems. It combines MICO's Model 691 electrohydraulic brake locks with Preco's PreView radar object detection.
When an equipped vehicle is shifted into reverse, a solid-state, 5.8 GHz pulsed radar sensor kicks in to sweep the area 5 million times/s. The detected distance to the closest object appears on an in-cab display within 2/10 s. Both moving and stationary objects are detected in a predefined coverage area; the detection range is 16 ft. wide and 9–26 ft. distant from the vehicle. If something is back there, the brake system locks hydraulic pressure in the service brakes. Should the driver need to closely approach, say, a dock or a pallet, there's a manual override that momentarily unlocks the brakes. Once this button is released, the brake lock re-engages.
The radar unit combine for safe backing up
The sensor, mounted at the rear center of the vehicle, ~36 in. above the ground, is encapsulated in a polycarbonate radome material and can operate at temperatures from –40°F to 185°F. Multiple sensors can be networked for large trucks requiring more coverage. The system is self-contained and is compatible with single-, dual-, or anti-lock brake systems and does not interfere with normal vehicle operation.
At present, the system is targeted for commercial vehicles and works only with hydraulic brakes, but MICO is working on an another version for air-braked vehicles. We would very much like to see it developed for all passenger vehicles, to prevent people from backing over bikes and, tragically, the children on them, in their driveways.