Driver's seat height safety problem

--- yes, eyes checked last month. I think not being able to use the break would be even more inconvenient

UPS says that the medium firm booster cushion will arrive sometime this Wednesday. These driver's seat boosters are wedges ~1" in front, ~3" in back and 14" deep (seat is ~17" deep). I also want to make sure that her head is at least 10" from the airbags.

 

--- what a great idea, thanks. I am a conservative old fusspot. One experiment at a time. There is no expectation that the current experiment will "solve" my wife's visibility issues; but, rather just optimize the "as is" factory configuration.

I have another experiment in the pipeline - with no parts purchased or ordered.
- a second driver's booster seat - extra firm (> 200 lbs) possibly sown to the one on order for stability.
- a lumbar (firm) cushion because she would be above the built in one.
Objective: reduce the amount of driver's seat cranking up & down - currently 2 to 3 times per day.

She is already using one of our kitchen cushions and it does improve her visibility. Lift is just a bit over 1" and it is not wedge shaped. You are right, stability is very important. I call these things experiments because they are allowed to fail.

One failed experiment was a stick on 2" convex mirror. That's where I learned that she was aware of the existence of cars in the "blind spot" but uncomfortable with their actual displacement, velocity, and acceleration. Yes, I am an engineer.

I need to figure out how to temporarily mount the suggested mirror without installing holes. Double sided mounting tape should hold for an hour or two.

Thanks again - great idea.

 

--- an automotive "convex aspherical lens" is usually in the form of a Fresnel lens made of flexible optical grade plastic. Sold in RV shops in the $10 to $20 range for use in the rear window of an RV. They typically provide 27 degrees down beam, 17 degrees to the side, and can be cut to shape with good pair of scissors. Usual size is ~10" x ~7". Just spray water on the window and the lens sticks. It is also easy to remove and leaves no damage. I had one in my VW combi bus for 20 years. After the driver's seat issues have stabilized. I intend to install one in the passenger side triangular "port hole" as the pillar blocks the visibility of bicycles coming from that particular direction.

Given a 10 degree down angle from the driver's position, the cumulative lens down beam is ~37 degrees. Trigonometry tells me that road level objects (curbs etc) can be clearly seen as close as 2' from the car.

- Neither of us can see the rear "port holes" much less what is on the other side (I am 6'2"). Our heads don't swivel that far any more.
- We've had the Prius for 3 months and are still getting used to it. We had our previous car for 22 years and had gotten very used to it

 

--- Good points!

The reason for all these types of mods is that they are experiments - which can fail. Most will. Which explains why I am looking primary at removable mods. I appreciate the liability issues (I write "Letters of Engagement" and "Letters of Acceptance" for professional gigs - I specialize in termination liability issues) and intend to do my due diligence.

In retrospect, a Hybrid Camry may have been a better choice (wrap around rear window), and we probably should have rented a Prius for a few weeks prior to purchase. It took over a month for these issues to surface. Cars have changed over the last 25 years (Duh!). I had a 1990 Honda CRX and my wife had a 1992 Honda Accord. Since these were personal cars, we had the seat tracks modified. Now, in retirement, we are down to a single car. The Prius is optimized for our kinds of use - unfortunately, not for our kinds of body

 

experiment interim status report:
Fresnel lenses:
I bought a 11" x 14" one ($24 incl tax) yesterday. I cut out pieces for two of my experiments. Unfortunately, I blundered, and both pieces were mirror image of what was required thus cannot be used as final solutions. However, I can and did install them on the outside of the car for testing purposes.

Observation: the 11" x 14" form factor provides too much light bend near the edges (especially the corners) and internal reflection exceeds refraction.

The piece affixed to the rear (vertical) window (a'la the use closest to the manufacturers intended) works brilliantly. It is mounted on the inboard edge of Toyota's etched tag which is on the passenger side of the glass - where driver's visibility is not blocked by the rear passenger side headrest. My test deployment shows that if "blind spot" objects can be seen in the side mirror, but not in the lens, then object is too close to pull in front of (< 6'). Conclusion: this configuration has some possibilities.

The piece affixed to the passenger side front port hole nominally works as I hoped, but suppresses too much of the potential image to be considered safe (reflection exceeds refraction).

Def: "blind spot". The area to the passengers side and behind the driver's seat that could contain a passing vehicle. I consider the area to be blind, even if the car can be seen, when the ability to judge relative displacement, velocity, and acceleration is compromised. Eliminating the "blind spot" usually requires that the area can be scanned via two or more windows / mirrors simultaneously.

I will get two of the 8" x 10" lenses for further testing.

 

- visibility experiment report:
- booster seat:
The Large Medium-FIRM Wellness Seat Cushion. Sold by TravelMate from Amazon.com ($26.50). Size: 18" x 14" x 1-3/4" to 3-1/2". Color: black.
has worked out perfectly. My wife's eye level is at the optimal (and target) height. She reports that her ability to judge the position of cars in the passenger side lane "blind spot" is much improved. These cushions and the factory seat do compress a bit, so weight is an important consideration.
The only negative is that the cushion does not self-center in the Prius's bucket seat. A rather trivial detail to my wife.
The 18" width is appropriate and the wedge shape (along with the 14" depth) does not seem to affect pedal reach.
- Fresnel aspheric lenses:
I will install the final (a cut down 8"x10") rear window lens later this week.
- Then we will let things stabilize for at least a month before reevaluating the situation.

Thank you all for your contributions and ideas. Meanwhile, I'll continue monitoring this forum.

 

We both have been doing a bit of your suggestion, here and there, for some time. I'll keep your points in mind. We both have handicap placards and find that bounding in and out of the car somewhat challenging - not to mention downright painful

Since you are a driver instructor: According to some of our friends, insurance rates will escalate when we are over 75 (not that far away) unless we take senior driver's refresher courses. Is this true?

Ref. Right side reference: Just for yucks, I measured just how close to the passenger side of car I could see a curb from the driver's seat. Laterally, no closer than 16' 8" and I am 6' 2". I haven't done the trigonometry yet. And, this being a Prius - what hood?

The "visibility problem" is not in detecting objects in "the blind spot" but in judging their relative displacement, velocity, and acceleration - in short, is it safe to change lanes? Obviously, we are concerned about 4 lane highways, which around here, are 45 MPH. Then there are the freeways ... The rear mounted wide angle Fresnel (RV) lens is proving to be quite a help.

A pleasant side effect of the booster cushion is that my wife (and consequently, myself) do not have to maintain the driver's seat in the full upright position (trays folded . The Prius headrest pushes forward quite a bit. We now have the seat reclined to the third detent position and it is a lot more comfortable.