42 ms·

In my experience, the 85th percentile is at the speedlimit + 10-15 mph. It's as if people have decided they're unlikely to be ticketed by going "only" 10 mph ov

• rhodysurf 10y ago
  In the US you usually wont be pulled over unless you are blatantly (10 mph+ depending on the road) speeding. Going 5 over will pretty much never get you pulled over unless you have a tail light out, or a warrant for your arrest or something
  • developer2 10y ago
    I think ticketing for 5 over would open up the floodgates to a debatably valid reason/excuse: a speedometer only reports accurate numbers when tuned to the wheel configuration. It's common enough for tire sizes to be changed on a vehicle, especially in regions where larger summer tires are swapped out for smaller winter tires, without the speedometer readings being adjusted for the new tire size. It could be argued that the vehicle owner is responsible for ensuring this adjustment is made every time tires are changed, but with no real way for the average consumer to verify or measure the difference, the fact is we depend on the business providing the service to do it for us.
    • Neliquat 10y ago
      While there is a standard for claims of speedo deviation, it usually is not claimed due to the 10mph or larger discrepancy commpn for tickets. You are right on about snow tires, but mine are larger, and my summer tires low profile. But those who swap wheels also tend to mentally recalibrate while passing those speed signs. I have to on all my motorcycles, as manufacuturers all seem to want me to think I am going 15% faster.
• graphitezepp 10y ago
  People have decided they are unlikely to get punished for going slightly over the speed limit because they are. I regularly pass speed traps on my daily commute going (precisely) 15 over. Would be nice if speed limit was actually the limit instead of the selectively enforceable suggestion that it is.
  • wyager 10y ago
    > Would be nice if speed limit was actually the limit instead of the selectively enforceable suggestion that it is. Why? It would add time to your (and everyone else's) commute, while simultaneously being unlikely to substantially improve traffic safety.
    • travisjungroth 10y ago
      I think there's an implied suggestion here that the number on the sign would go up to match the enforcement, not the other way around.
    • aeorgnoieang 10y ago
      Probably because some people values clear rules that are enforced; not because they actually want to a slower commute.
    • Arizhel 10y ago
      He obviously wants the speed limit on the sign raised to what the actual enforcement is (currently the limit +15 or so).
• wyager 10y ago
  The heuristic I tend to follow is "9 you're fine, 10 you're mine". It has not failed me yet. Traffic cops are reasonable unless they're running behind quota.
  • douche 10y ago
    > Traffic cops are reasonable unless they're running behind quota It's kind of funny to watch on the last two or three days of the month how many of the state troopers are out on the interstate, doing speed traps all day long. The rest of the month, you'll almost never see them, unless they are escorting an oversize load.
    • Neliquat 10y ago
      Just a friendly reminder (most) quotas are techically illegal, yet we still all accept it as the norm.
    • brewdad 10y ago
      IF a department was going to set up quotas for speeding tickets but also wanted to slow drivers down as much as possible, why not have the quota deadline be rolling? Officer Jones has to meet his quota by the 3rd of the month. Officer Smith must meet hers by the 5th and so on. Quotas without the end of month blitz and more reliable enforcement.
• bspn 10y ago
  My wife was born and raised in the Southern US, and whenever we travel on the interstate system here she assures me that so long as I remain within 15mph of the posted speed limit I'll never be ticketed. When she first told me her theory it's fair to say I was a deep sceptic (as a foreign-born LPR), but nearly a decade on and she hasn't been wrong yet. I will admit though, she counsels me against following the rule in Virginia because the cops there don't mess around. EDIT: I should add that 15mph over the limit is usually "going with the flow". If the other cars are traveling at 70 then 85 really stands out.
  • mikeash 10y ago
    Yeah, absolutely do not follow that rule in Virginia. We have roads where the speed limit is 70MPH. If you're driving 80MPH or over, it's automatically a reckless driving charge, which is an actual crime, not just a moving violation. And if your attention drifts a bit and you accidentally break 90MPH, you'll probably end up in jail. My usual rule is 5MPH over. I sometimes increase it to 10MPH, but it works almost everywhere.
    • Neliquat 10y ago
      In general: 5 over is safe everywhere in the USA except school zones. 10 is generally safe in suburban and rural areas. 14 over on highways, unless mitigating situations exist (bridge, visibility, twisties) Beware, almost every area has some county or township that abuses their little patch of highway, and they tend to be well known to locals, but prey on passers by. This is not bulletproof, but has been my experince.
      • brewdad 10y ago
        This is true but personally I would rather see this shift to something closer to +10%. Going 35 in a 25 mph residential zone puts anyone not in a car in significant danger. Going 27 or 28 doesn't change the risk nearly as much. This rule of thumb still allows for 61 mph on urban freeways and 77 to 83 on rural interstates.
  • tropo 10y ago
• icelancer 10y ago
  It also helps that every speedometer installed in cars is 1-3 MPH slow on purpose (estimating above true velocity is obviously a real problem, and I believe results in fines to the manufacturer). Plug an OBDII reader + app into your car to see the true velocity.
  • falcolas 10y ago
    Well, true velocity as reported by the car. Slop in the drivetrain, tire inflation differences, temperature differences... these can add up to up to 10% differences between your speed as reported by radar/gps and what your car measures from the drivetrain.