Just to repeat my previous post: "Actually, it is because Manufacturer's don't want the liability if the speedo should read LESS than the actual speed, and you get a speeding ticket. It typically will read about 2-3 mph high." To add to that, I believe there is a "United Nations" agreement that specifies this discrepancy. Actual speed being 2MPH lower than the speedometer reading is what I'm seeing as well.
Yes, but nearly all the signatories to that particular UN standard (the one linked from PriusChat multiple times in the past decade) are EU and Asia-Pacific countries. None are in the North/Central/South Americas region.
How much hand-wringing can we do over this? If you're adamant to do the actual limit: "speed" by 2 mph, done?
For me, it’s a question of accuracy. “Sir, do you know how fast you were traveling?” “I think so, Officer. You see, the speedometer said I was driving 67, which - according to the United Nations - actually means I was driving 65.” “Step out of the vehicle, sir.”
On Toyos the speed was 1 mph low according to Waze and Garmin... temporarily on Hankook 737 and now the speedometer is 2 mph low... switching to Bridgestone next week...
They’re my hands, I’ll wring them if I want to! But thanks for taking the time to add nothing to the discussion.
I have driven a 2014 Prius V for the last three years. I installed a dash camera when I took ownership. On this dash camera it displays the gps-based speed of the vehicle. There has always been a discrepancy between the gps and the vehicle. The gps says 70 mph and the vehicle indicates 74 mph. However, about two weeks ago my dash camera gps and the vehicle indicate the same speed. Things that make you go hmmm. Has anyone else experienced this phenomenon? I know that the speedometer is electronic, as opposed to a gear-driven cable, And I am sure that tweaking a few lines of code can result in different speedo readings. My conspiracy theory me has believed that the 'faster' reading was just industry's way of reducing speeding on our nations roads. Is Toyota secretly contacting my car to update software?
I don't think the gen 3 or v had capability for that kind of secret update. It's an open secret around here that the combination meter display exaggerates. You don't even need to compare it to GPS-indicated speed: just use any OBD-II scan tool that can show you live data, and have it show you the actual vehicle-speed PID the brake ECU computes from the wheel-speed sensors. You'll see that it's accurate—and that's the exact number that the combination meter requests from the brake ECU over CAN—and then exaggerates for display. I'm kind of surprised you had that moment where the combo meter and GPS reading didn't look different. I doubt anything changed about the car. Maybe the GPS reading was less accurate than usual just then. Something about the terrain, maybe?
