Determining the Width of Streets by Listening to Traffic
Students who understand about traffic lanes are ready to learn to identify how many lanes of traffic are in the street and how far away from them the first lane is by listening.
Most students can learn this with the following exercise:
- identifying which lanes the vehicles are in as they pass.
It usually takes students only about 10 minutes before they can listen to the passing vehicles and correctly identify which lanes they are in, and how close the first lane is.
- Have the students face a street with multiple lanes of traffic going the same direction and listen to the vehicles.
- As the vehicles approach, tell the students which lanes those vehicles are in and let them listen to what vehicles in that lane sound like.
- When the students are ready, let them guess which lane the vehicles are in, and see if they are correct -- if not, you can resume telling them the lane before the vehicles arrive, so they can listen again to what vehicles in each lane sound like.
- As they become skillful, ask them to identify how far away the first lane is (that is, whether the vehicles in the first lane are passing within inches of the curb, or there seems to be a shoulder or even a parking lane between them and the first lane).
In the two photos above, I am reporting which lane the approaching vehicle is in, and the students listen to what a vehicle in each lane sounds like.
In the third photo, I let them guess which lane the vehicles are in, and tell them if they are correct after the vehicles pass.
Where to train this skill?
The ideal street for this training is a street that has at least 3 lanes going in the same direction.
For example, even though the street in these photos is a two-way street, it has 4 lanes with traffic coming from one direction, which is what we need.
A one-way street with at least 3 lanes would be great, too.
The reason you want the traffic all going in the same direction is because you don't want the student to be able to guess which lane a vehicle is in by the direction it is traveling -- the vehicles in all the lanes that you are using should be traveling the same way.
- putting it all together to determine the probable width of an unfamiliar street:
Once the students can identify which lane the vehicles are passing in, they are ready to put it all together and determine the probable width of streets.
Have students stand at the edge of an unfamiliar street and listen to which lanes are used by the traffic coming from the left (the near side of the road) and which lanes are used by traffic from the right.
They can also determine how far away the nearest moving traffic is, and consider whether there is a shoulder or some easement to cross before reaching the first lane.
If the nearest moving traffic seems far enough away that a car could park between it and the student, perhaps there is a parking or a turning lane, or a lane that drivers use when the traffic is congested.
The students will then use knowledge of typical street geometry to calculate how many lanes wide the street is likely to be.
For example, if they can hear no traffic in the first lane, traffic from the left in the second lane, and in the third lane they hear traffic from the right, they know that there are only 2 lanes coming from the left, one of which might be a parking lane or turning lane (or the first lane is wide enough to allow parking).
Since most streets are symmetrical, they can guess that there are probably 4 lanes altogether, possibly including parking lanes on each side of the street.
- figuring out how much time is needed to cross the street:
Students can learn how much time they typically need to cross streets of various widths if you time their crossings for streets that are two lanes wide, 3 lanes, 4 lanes, etc.
Of course when estimating how long it will take them to cross, they should count any parking lanes that they have to cross.
For example typical residential two-lane streets usually have enough room for cars to pass each other while cars are parked on the street,
so their actual width may be the same as a street with 3 or 4 narrow lanes.
- Want to see the training in action?
In 2011, this training was done with French Canadian teenagers who are blind or visually impaired -- click here if you want to read about it and watch the videos.