Assessing & Developing Judgement of Safety for Crossing Streets Which Have No Traffic Control

by Dona Sauerburger & Dr. Mary-Maureen Snook-Hill
Format adapted for the Web by Ray Dragon

Note: So as not to have this page take a long time to load, all the associated photos have been put on separate pages - you simply need to click on the links to view the photos.

What criteria do you teach your students to use

to determine whether they will be safe when crossing streets where there is no traffic control?

(A street "with no traffic control" is one where there is no control signal or stop sign for traffic on the street being crossed.)

We propose two criteria which must both be satisfied:

Criteria # 1 - There must be gaps between the vehicles that are long enough to allow them to cross (in other words, the traffic must not be too busy).

Criteria #2 - They must be able to hear or see the traffic well enough to recognize when there is nothing coming that could reach them during their crossing. "Take the "picture quiz" to see how well you can predict whether or not a person can hear the cars well enough to satisfy Criteria #2."

How did you do on the picture quiz?

You may have discovered that it's not always easy to predict whether or not one can hear well enough, since sometimes cars can be heard long before they are seen (streets A and C from the west) but sometimes they can't (street C from the east), and sometimes they cannot be heard until long after they are seen (street D). Also, conditions can sometimes change, as happened at street "E."

Our students need to recognize those situations in which they can hear or see well enough, and those in which they cannot.

• How can we determine which situations are which?
• How can we teach our students to recognize the difference?

Sauerburger developed the Timing Method for Assessing the Detection of Vehicles (TMAD) to determine whether or not a person can detect the traffic well enough. The TMAD is described below. A procedure to access and develop judgement of the detection of traffic, using feedback from the TMAD, is also described below.

A study was conducted in 1995 by the Orientation and Mobility Department of Peabody College to:

1. consider the viability of the TMAD for assessing students' ability to detect vehicles in various conditions; and
2. consider how effectively the procedure described here could develop the judgement of visually impaired students in those situations.

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Timing Method for Assessing the Detection of Vehicles ("TMAD")

1. Determine the time needed for the crossing by estimating or timing the crossing (see figure A 1-3).
2. While standing at the curb, wait until no approaching vehicles are detected (a perceived lull in traffic).
3. Start a stopwatch when something is seen or heard that might be an approaching vehicle (figure B-1).
4. Stop the watch when the approaching vehicle passes in front of you (figure B-2).
5. Compare the time of the approaching vehicle from detection to arrival with the time you need to cross.

a. If the vehicle reached you in less time than you need to cross, you can conclude that you can't detect the traffic well enough in those conditions to know when it's clear to cross.
b. If the vehicle was detected with enough warning, continue timing vehicles until you have observed and timed one of the vehicles that reaches you in the shortest time once you detected it (we shall call these vehicles the "worst cars"). If you detected all the vehicles, including the "worst cars," with enough warning to allow you time to cross, then you can conclude that you can cross there safely under these conditions.

Note: This requires that you observe and time your detection of at least one of the "worst cars" (see Peabody Street-Crossing Study, Objective #1).

Procedure to develop judgement of the detection of traffic

1. Go to an appropriate intersection that has frequent but intermittent traffic.
2. Have the students determine the street's width and understand how much time they need to cross.
3. Have the students judge whether they can hear or see the traffic well enough to know when it is clear enough to cross or, conversely, whether the vehicles are appearing without enough warning.
4. Use TMAD to provide them with feedback about their judgement.
5. Repeat this procedure of providing feedback and testing their judgement under a variety of conditions, until they can accurately judge when the conditions are too poor to know when it's clear to cross.

• Note that the conditions (masking sounds, lighting conditions, etc.) must remain relatively steady long enough to test whether the student judged the situation accurately.
• To test a variety of conditions, you can go to various intersections, or you can vary the conditions at one intersection (for example with various masking sounds, or objects to block the sound or the view).

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Intrigued? Convinced? BUT DON'T KNOW HOW??
Then ask about the videotape that illustrates it!

In spring of 1996, Dona Sauerburger put together a videotape at streets where there is no traffic control, showing:

• Why we need two criteria for safety (including illustrations at several unexpected intersections);
• The TMAD used with several people;
• The "Procedure to Develop Judgment of the Detection of Traffic" used during four sessions with one person;
• The TMAD used with a woman who must decide whether she is safe using her vision or her hearing to detect cars.

For more information, or to order your copy, contact Dona Sauerburger at:

sauerburger@mindspring.com

1606 Huntcliff Way
Gambrills, MD 21054, USA
Phone: 301-858-0138