study questions;
checklist for this procedure;
forum discussion;
simulated workshop demonstrating use of this procedure
This procedure uses the Timing Method of Assessing the Detection of Vehicles (TMAD) in a variety of conditions to provide students with feedback about their judgment as to whether they can hear / see the vehicles far enough to be confident that it is clear to cross whenever they hear/see nothing coming.
SITE SELECTION:
The best places to use this procedure are crossings where:
there is frequent but intermittent traffic
Your students will be timing their detection of vehicles after everything has become quiet or they see no vehicles, so if the traffic rarely gets quiet or vehicles rarely approach, you'll be there for a long time, waiting for those opportunities!
So you look for a place that has some approaching traffic and then some quiet, then traffic, then quiet, etc.
the auditory / visual conditions are steady
Your students will assess various situations, and then you will test their judgment to give them feedback about their accuracy.
You won't know if their assessment of the situation was correct or not if it changes before you can test it, for example:
- if a lawnmower starts up after a student who uses hearing assessed the situation, or
- if a student who uses vision assessed a situation in cloudy conditions and then the sun comes out.
Therefore you need a site where the conditions that affect their ability to hear / see the traffic will remain steady long enough to test their judgment of the situation.
PROCEDURE:
Step 1: Student determines crossing time
Step 2: Student judges (assesses) situation
Have the students try to judge whether:
- they can hear or see the traffic well enough to know when it is clear enough to cross or
- the vehicles are appearing without enough warning.
Allow them as much time as they need to observe and listen, and perhaps prompt them with questions about the traffic such as:
"If you had started to cross just before you heard/saw that car (that is, when it was still quiet and/or you didn’t realize something was coming), would you have finished your crossing before it passed? or would that driver have had to slow down to avoid hitting you?
Listen to /watch the approaching traffic for as long as you need, and tell me if you think you can hear/see all vehicles here well enough to know you have time to cross, or if you think it's not possible to hear / see some of them until they are too close."
Students who rely on their hearing can assess noisy situations as long as the ambient noise level does not fluctuate.
But when they do the assessment (that is, when they listen to the approaching vehicles and guess whether they can hear them well enough), they should do so when it is as quiet as it gets in that situation.
Many students are unaware of the presence of noise and how much it impacts their ability to hear approaching traffic.
If there happens to be a temporary masking sound when they try to draw conclusions about how well they hear traffic, encourage them to notice that there is a noise present (an airplane, receding car, lawnmower, etc.), and notice the effect of the noise on their ability to hear the approaching traffic.
Step 3: Student gets feedback about accuracy of judgment / assessment
Use the Timing Method for Assessing the Detection of Vehicles (TMAD) [recommended by the Self-Study Guide -- page 4] to provide students with feedback about their assessment of the situation.
If their assessment was wrong, discuss what they could have noticed and how they can improve their assessment next time.
Remember that the conditions (masking sounds, lighting conditions, etc.) must remain relatively steady long enough to test whether the student judged the situation accurately.
If the conditions change before the student's assessment can be tested, ask the student to assess new conditions and then test that assessment.
Step 4: Repeat!
To ensure that students can recognize situations of uncertainty for gap judgment, it is important that they successfully analyze at least one situation in which they
- CAN hear or see the traffic well enough to know it's clear to cross when quiet,
and at least one situation where they
- CAN NOT hear or see the traffic well enough, and they are in a situation of uncertainty for gap judgment.
To test a variety of conditions, you can go to various intersections, or vary the conditions at one intersection (for example, add a steady masking sound, or set up a barrier to block the sound or the view).
MASKING SOUNDS:
Again, for students who use hearing to cross streets, this is an opportunity not only to have them learn to assess situations realistically,
but also to understand the effect of noise on their ability to hear approaching traffic.
Some students are able to learn this simply by noticing how close the vehicles can get before they are heard when there is a masking sound from receding vehicles or other noise.
For students who have difficulty understanding this, it can be effective to use the TMAD to compare the detection time of vehicles that approach when it is quiet to those that approach when it is noisy.
Self-Study Guide: what next?
If you're following the Self-Study Guide, you should have already read the "Timing Method for Assessing Detection of Vehicles (TMAD)" (page 4 of the Self-Study Guide) before you go on.
Your next step is to return and finish reading "Teaching at Crossings with No Traffic Signal or Stop Sign" (page 2 of the Self-Study Guide)
Return to Teaching at Crossings with No Traffic Signal or Stop Sign
Return to Self-Study Guide:
Preparing Visually Impaired Students to Assess and Cross Streets with No Traffic Control
Return to Home page