Speed studies had been performed through manual methods to measure time vs. measured distance. These involve measuring the time required for a vehicle to transverse a measured course. There are a number of devices that can be used to measure time. One of the manual means involve using a stopwatch to measure time. The measured course is specified at the location under study, where two observers cooperate to record time, one at each end of the course. One of the observers starts the watch when the vehicle passes and stops it upon receiving an indication from the other observer that the vehicle passes the end of the course. The length of the course may range from 25m to 75m, where the length depends on the average speed and the location under study (shorter lengths at low speeds and CBD sections and longer lengths at higher speed sections).