So what...it's only 5km/hr more

And bigger vehicles have bigger brakes, larger swept area....

Interesting data on the weight/braking/stopping. Clears up a few things!

As far as the risk of a cyclist being fatally injured goes, I think I have the data somewhere, I'll see if I can find it. I can't imagine it being that dissimilar to the risk for pedestrians. Most of the information on the risk-of-death-versus-type-of-collision came from the New Zealand Ministry of Transport, I'll see if there's any data out there.

Along with this.

Is it a law soon all new cars must come with electronic stability control?

I know there was talks of this.

Is it also law all new cars must come with disc brakes on all 4 wheels. I dont remember i thought i heard some ramble about this.

Didn't hear about those. I heard that some people might want ESC but that could be a hinderance to "expierienced" drivers

I did hear about stability control, along with TMPS, being mandatory. Stability control is different from traction control, in that stability control tries to keep you straight on the road and traction control keeps you from spinning your tires. I like stability control but hate traction control. TC helps a bit with open differentials, but most of the time it feels like you're driving on sheer ice because of the way the engine cuts back on power.

Racer - you say mass has no effect when the tires are locked, and that sounds right even though it's late at night and I haven't really looked at the formulas.

But what about throwing ABS into the mix? I also bet that most seasoned truckers are pretty good at threshold braking. To me, it seems logical that threshold braking would produce shorter stopping distances than locked tires, but a light vehicle will stop even shorter than a heavy vehicle using threshold braking.

Bear - to be fair, let's assume both vehicles are travelling neck-to-neck at the moment they both see the hazard. The faster vehicle would still be at a disadvantage, even assuming identical stopping distances:

A: 108.....reaction time.......braking......stop
B: 113.....reaction time............braking......crash

racer wrote:

If the reaction time is approx 0.1 s, in that time the driver at 113 will travel exactly 139 mm (5.5 in) ahead of the 108 guy. If you take the reaction time to be 0.2 seconds, that's 278 mm (11 in)... When you are taking 50 m to stop, that difference in negligible, I also did round well more up when calculatin for 113 guy as opposed to 108 dude.

reaction time is 1.5 seconds (time person sees the danger, processes "oh *EDIT*" in the mind, then tells the body to move the foot, then the foot to depress the brake)

that being the case, in 1.5 seconds the faster driver will move ahead by 2083 mm (2.1 metres). In the end the numbers are such that they do not differ much from what I have...

Again, going those speeds, which are reasonable for 400-series, you simply do not see such a situation. On the city roads, where a truck pulling up on you is much more feasible, when you go 60 you take 15.75 m to stop after you hit the brakes, while going 65 you will take 18.5 metres, or add 2.1 metres and you end up with 20.55 m. A lot is dependent on the speed you are travelling at - ABS on or off, driver skills are all moot when it comes to "oh *EDIT*" reflex, which forces the driver to floor the braking pedal (and yank the handbrake if s/he can still think straight), the stopping distance will always be proportional to the square of the speed.

ABS and the rest can work great, but we are taking worse-case scenario. If you use tires with better grip (you will also see more smoke) you will reduce your stopping distance. And some people will try to drift out of trouble, which might work, but for which ABS does not help at all... The only real practical use for the ABS is stopping on icy road, and as we all well know, driving 100 on ice = pileup, be it 80 or 120.

(and yank the handbrake if s/he can still think straight),

and downshift and throw both hands out the sunroof for aerodynamic drag

Reflections wrote:

(and yank the handbrake if s/he can still think straight),

and downshift and throw both hands out the sunroof for aerodynamic drag

or the coefficiency of "soles" vs road...seems to work for the Flintstones!!

Big rubber boots or sandals????????/

Reflections wrote:

Big rubber boots or sandals?

I was thinking of a boat anchor. Works great when there's potholes!

Haha some parts of the 401 in toronto look like a giant slice of swiss cheese there is so many holes.

The worse part is you cant close that highway or the traffic backup would be ridiculous.

I was thinking of a boat anchor. Works great when there's potholes!

Haha some parts of the 401 in toronto look like a giant slice of swiss cheese there is so many holes.

Ah HA......there is the cause.....too many boat anchors making holes in the road!