TIMING METHOD FOR ASSESSING DETECTION OF VEHICLES (TMAD)

Answers the question: “Can I see/hear vehicles far enough away to be certain that when it’s quiet, it is clear to cross?”

Procedure:

1. Determine the time needed for the crossing either by an estimation based on walking speed and the width of the street, or by timing several crossings and using the longest time (do not use the average time, since you are looking for the worst‑case scenario).

2. While standing at the curb, wait until no approaching vehicles are detected (a perceived lull in traffic). If you depend on hearing, this should be at a time when you think it is quiet enough to hear approaching traffic sufficiently.

3. Start a stopwatch when something is seen or heard that might be an approaching vehicle.

4. Stop the watch when the approaching vehicle passes in front of you. If the time recorded is less time than you need to cross, then you know that if you had started to cross just before it was detected, the vehicle would have reached you before you finished your crossing. If the recorded time is longer than your crossing time, you would have completed the crossing safely even if you had started just before it was detected.

5. Continue timing the detection of approaching vehicles until sufficient samples have been taken to conclude whether you can detect vehicles well enough to know when it’s safe to cross there.

a. If you started the timer the instant you first detected anything that might possibly be a vehicle, yet a vehicle reached you in less time than you need to cross, there is no need to continue. You now know you cannot detect all the vehicles sufficiently under the condition that it was detected, and you should consider alternatives or be aware that if you cross there, you are depending on drivers to see and avoid you.

b. If you detected all the vehicles, including one of the “worst cars” * with enough warning to allow you time to cross, then you can conclude that you can cross there safely under those conditions.

* The “worst cars” are those vehicles that reach you in the shortest time once you detect them. We want to know whether even the “worst cars” can be detected with enough warning. Thus, we continue to time our detection of approaching vehicles until we are satisfied that we have timed the approach of at least one of the “worst cars.” That is, we continue until we are confident that if we timed the approach of any more cars, we would be very unlikely to find one that reaches us in less time than the cars we’ve already observed.

NOTE: For a suggestion using the TMAD to teach people to be able to recognize situations where they can not detect traffic

well enough to know if there is a sufficient gap to cross, see Procedure to Develop the Judgment of the Detection of Traffic.

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