I am posting this on behalf of Kim, a blind friend.

In summary the problems is that people who are blind or with certain
disabilities are in danger of being hit by new energy efficient cars
which are silent. I hope this posting will raise awareness and
motivate those who can contribute to solving the problem to take
action. I will forward any reply postings to Kim.

Responses to Kim
Two auto companies have contacted us and said that they are aware of
the problem and are passing it on to their engineering departments. I
pointed out to them that blind people need to be involved in the
testing of whatever noise they choose to use in the hybrid cars.
Someone in a wheelchair wrote to say that she uses traffic noise a lot
as it is difficult for her to turn her head to see all traffic coming
from behind.
Someone said that hybrid cars approaching to pick them up were totally
silent and because they were blind they did not know their ride was
there. This could be a problem if there are hybrid taxis.
Someone pointed out that kids playing on or near the edge of the
street would not hear the hybrid cars and drivers must be vigilant for
them.
A sighted driver pulled into a parking space, got out of his car, and
was taking things out of the back seat.  A hybrid car pulled in beside
him at this moment.  He did not hear a thing and was scared by the
sudden presence of a vehicle.

Solutions suggested include:
Having a noise from the exhaust fan of the hybrid car.
Having the wheels or axels make a noise.  Note this would not assist a
person who is blind to read traffic if a car is totally stationery at
an intersection.
Having some sort of noise maker installed into the hybrid car like a
beeping truck when it backs up.
Having a computer chip in the hybrid and in a dog's harness or white
cane so that they make a noise when they are near each other.
Having a device made that a person who is blind can hold and it will
tell them if there are vehicles in the vicinity.  One problem with
this would be if it malfunctioned and also another problem is the way
you point the device and if it reads all traffic at all speeds.  Also
this would not assist you with cars that pull in or out of driveways
or parking lots.
Putting a section in all manuals for hybrid cars to make sure to watch
for pedestrians who are blind or visually impaired.  Public education
is always good however people tell me they don't read their car
manuals.
Make sure as a blind or visually impaired pedestrian that you are
always as visible as possible.  Some people wear very bright vests
obtained from shops for cyclists. Guide dog harnesses can have
reflective tape on them.  There are also lights like cycling lights
that you can wear if you are concerned about visibility.

Here is KIM's original e-mail:
This is about the an issue with quiet cars.
I have been blind since birth and travelled with a white cane from age
6 on.
For the past 13 plus years I have been partnered with three wonderful
guide dogs.  I have always considered myself a competent and confident
traveller and thought that I could overcome any challenge in my
environment.
Recently, while walking on a very quiet residential street with a
sighted friend, we paused at the corner.  There was no background
noise, no traffic noise, no loud music, etc.  I told my dog forward.
She refused to go.  My friend said, "There is a car on your right
coming through the intersection." I heard nothing. It was a quiet or
hybrid car.
I have since learned that these vehicles make absolutely no noise when
going
at low speeds or when idling waiting for a light to change.
Contrary to popular belief, our guide dogs do not read the traffic
lights for us.  When I reach a lighted intersection, I listen for the
noises of traffic flow.  If the traffic is flowing parallel to me, it
means my light is green.  However, I often wait for a fresh light to
cross the street.  If
the traffic is perpendicular to me (moving across in front of me) the
light is red and I wait for a green light.
If the intersection was full of quiet cars, I could not read traffic
and would not know when to give my dog the forward command.
But this is not the only issue.
When I stop at the corner of a stop street with no light, I listen to
make sure no traffic is approaching before giving my dog the forward
command. Again, if the intersection was filled with quiet vehicles I
would not know when it was safe to do this.
When I travel on a sidewalk-less road, I walk on the left hand side
with my dog on my left facing traffic.  When cars approach us, I turn
us into the curb edge to make sure we are out of the line of fire!
Again, I would not know when traffic was approaching in this
situation.
When walking through parking lots, I would not know if quiet cars were
suddenly turning in front of me or coming from behind.
When walking down a sidewalk, I would not know if a quiet car was
pulling in to or out of a driveway.
Many of our big cities are now filled with wheelchair ramps at curbs.
This is generally a good thing but makes lining up with an
intersection trickier for someone who is blind. I use traffic noise to
make sure I am pointing in the correct direction for a street
crossing.
This is especially useful when coming to rounded curbs which make it
even more difficult to line up with intersections.
In the winter here in Canada with snow covered corners, lining up with
intersections is trickier.
When it is windy or raining hard or in winter when you need to wear a
hat, traffic noise is more muffled.
This issue really concerns me as I cherish being able to travel
independently.
I would just like these cars to make some kind of noise.
Please pass this on to anyone you like.

CWA