A Primer on Technology

Light metro

The REM is an automated driverless light metro system. It has its own separate corridor which can be an elevated cement guideway or an underground cement tunnel. Trains consist of two to four vehicles moving on tracks. Vehicle Control computers communicate with on board computers whose data is transmitted through a cable laid along the tracks.

Light rail

Runs on fixed rails in right-of-way that is often separated from other traffic. Rails can be existing railway tracks or new tracks added to city streets. Light rail is typically driven electrically with power drawn from an overhead electric line via a pole or a pantograph. There is an operator on board the vehicle.


Same as Light rail except that they run mostly on public city streets. Tram signal priority using an integrated optimization model lets operators extend green lights without causing excessive delays to other vehicles. Bombardier’s Flexity model is 2.65 meters wide, 32.5 meters long, and is currently in use in Toronto.

Bus Rapid Transit (BRT)

Buses have their own right of way, longer spaces between stops, shorter distance between vehicles. By prohibiting other vehicles from making right turns in front of them, significant time savings occur. Cheaper than rail transit but slightly more expensive than regular buses.

Active Transportation

Bicycle lanes enable cyclists to ride at their preferred speed without interference from prevailing traffic conditions. They still have to stop at traffic lights and obey road courtesy, but the marked bike lane restricts encroachment from motorized traffic thereby protecting cyclists from injury.

Tram Trains

Developed in Karlsruhe, Germany, they operate on city streets and on railway lines shared with conventional trains. They are often used to connect railway lines to city centers.