In another topic, SillyRoadRules wrote:
Can I ask the PO's herein do they take account of the vehicle when deciding if it's driving at an appropriate speed?
I ask for a reason I'll detail here when I've seen some replies (and it's an interesting story).
P
Almost everything affects appropriate speed.
- vehicle
- driver
- road width
- slope (uphill or downhill)
- hazards ahead
- possible hazards ahead
- weather
- road surface
- light (day or dark, oncoming headlights, low sun, glare, etc
- and plenty more...
'Vehicle' is a funny one. Under most circumstances, and especially at lower speeds, vehicle capabilities aren't that different. Some vehicles (Maestros and Allegros come to mind) tend to lose stability with increasing speed.
I remember a loan Maestro on the A3 at an indicated 75mph - I actually needed all three lanes clear to be confident that I could gather it up. You won't be surprised to hear I didn't keep the damn thing running at 75mph. At 60mph it seemed OK. I suppose there was something wrong with it (dampers?) to make it as bad as it was.
I've also noticed several German saloons where 'everything smooths out' somewhere around 110mph. I guess this is 'autobahn tuning' in the suspension, and when conditions are suitable it's a shame not to be able to take advantage.
The bottom line is this: Up to about 50mph the vehicle does not make much difference to maximum safe speed. Above 50mph some vehicle designs may become progressively less stable and controllable and yet others may become more stable and controllable even at very high speeds.
I've often wondered how the drivers of the likes of the dangerous Maestro perceive the drivers of the likes of the German saloons passing them at 50mph faster. If they've based their impression of speed on the capabilities of their own vehicle, the higher speed traffic would seem suicidal.