Passing Aid System Test Area | Newport, Palmyra, Canaan

Imagine driving down a road at the speed limit only to come across a 500 poundah apparently incapable of reading big black numbers on a reflective white sign stuffed into a Plymouth Voyager adorned with Dole/Perot '96 stickers doing 30 in a 45. It's a twisting rural road, between the hills and curves you won't have an opportunity to pass this person for miles. Your choices are to resign yourself to arriving late, or to bite your lip, floor it and try to keep your underwear clean. Wouldn't it be great if there were a technological solution that would allow you to pass other drivers on corners and blind hills?

With work done by the State of Maine with money from the Federal Highway Administration there almost was.

MDOT Computer, late 1960s

The February 1971 edition of Popular Science optimistically reads:

Most of the hardware is ready for an electronic system that will help you pass safely -- and more often -- on the busiest two lane highways...this remarkable Passing Aid System (PAS) developed for the Federal Highway Administration will automatically detect the presence of all cars in the zone it covers, determine their direction and speed, and tell the prospective passer how many seconds he has to pass. The information will be beamed to either a dash-mounted flasher in his car or to a roadside display unit.

Between Newport and Canaan there were once four hundred roadside sensor boxes (every 200') connected to cables beneath the road that would transmit data back to a central computer in Palmyra and notify the driver via electronic roadside sign or dash-top box whether or not it was safe to pass, as well as how much time they have to pass. In 1969 the Lewiston Evening Journal reported that the system would also notify motorists of obstacles that had entered the road. The system's purpose was to allow motorists to pass safely on corners, hills and at night. It was thought to be more cost effective than other safety improvement alternatives.

Popular Science, February 1971 (click to enlarge)

The system was designed specifically for two lane rural roads as it was less expensive to outfit them with this electronic system at the rate of $50,000/mile than it was to widen these routes to four lanes at the cost of $750,000 per mile. The chief of the traffic systems division for the Federal Highway Administration in 1971 had even offered this system as an alternative to modernizing rural routes at the cost of $400,000 per mile. (Popular Science.)

While the system made use of Raytheon hardware for its road side sensing units, the brains of the operation were a computer system housed in a long and narrow brick building that used to occupy a space on the northern side of Rt 2 just to the east of the abandoned 'rest stop' outside of Palmyra. This computer would take information from the roadside/subterranean sensors, analyze it, and notify the motorist whether it was safe to pass, how much time they have to pass, or even if they should pass. 

This was the very first system of its kind to be developed and tested in the United States and the Maine Dept of Highway's tests were making headlines across state lines.  By 1972 the project was scrapped despite the National Highway Administration's conclusion that the system was technologically and economically feasible. The reason given? Re-prioritization of projects.

Unfortunately none of that infrastructure remains. I've highlighted the test track route.

Articles:

Passing Aid System awarded to low bidder - Lewiston Daily Sun - 1969

Experimental passing aid system - Lewiston evening journal - 1969

Travel quicker on two lane highways, research shows, Popular Science, February 1971 

Passing Aid System Altered - Link1, Link2, Bangor Daily News - 1972