Passed many average speed check areas on Tuesday so I thought I'd keep check by using my ford focus 2013's average speed function on the dashboard.

 

Pottering along id be doing 70mph, reset the average speed clock and watch it. Keeping the speedometer needle at 70 exactly , I was surprised to see the average speed computer only ever stayed around 67mph... 

 

Thinking I maybe slowed a little at one point, I thought I'd test it again, this time pushing the needle OVER 70mph (recon doing 73 at one point but being mindful of not going over the limit) - again, the trip computer reports an average speed of 68mph despite the needle not ONCE going below 70mph.

 

Could it be my speedometer is out of calibration? I did reset the average speed in between each test for fresh checks.

 

Maybe the many SUV drivers up my ***** while doing the speed limit weren't such naive / impatient *****rs as I first thought, maybe I've been driving like a granny for the last few years LOL

 

Just think of the years of my life I could've been wasting when I could actually be getting to my destination quicker 🤣

All UK (and probably the whole world) speedos are deliberately set to read up to 5% high. Therefore  the following will be true:

 

Speedo shows 30mph = actual speed 28.5mph

Speedo shows 31.5mph = actual speed 30mph

 

Speedo shows 70mph = actual speed 67mph

Speedo shows 73.5mph = actual speed 70mph

All Ford speedos that I have had for at least the last 15 years have always over read by between 2 and 3 miles an hour at all legal road speeds. I just set cruise control or speed limiter for 2mph higher than the speed limit, so cruise set for 72mph actual speed will be 69mph, cruise set for 32mph actual speed 29mph.

1 minute ago, pcaouolte said:

All Ford speedos that I have had for at least the last 15 years have always over read by between 2 and 3 miles an hour at all legal road speeds.

I've come to the same conclusion. Still set my cruise on the limit speed though for a "safety margin". 

Thanks I didn't know that. I recon if I did 31 in a 30 by Speedo speed, the local enforcement community speed watch will be on me anyway 🥴🤣

 

 

6 minutes ago, mburdett555 said:

local enforcement community speed watch 🥴🤣

Funny thing about that. My Parish Council reckon that the biggest issue raised with them is speeding through the village. Yet almost every month they put a plea in the newsletter for volunteers to operate the speed gun. I haven't seen it for several.years now so obviously the complainers can't be ar*ed to do anything about it!

I have been past fixed and mobile speed cameras with cruise set 2mph above the limit and haven't yet had a speeding ticket in 45 years of driving. The old speedos where the needle wobbled up and down while you travelled at a constant speed where much more random than the current electronic ones. My Puma has a digital speedo and it is still the same amount out.

1 minute ago, Eric Bloodaxe said:

volunteers to operate the speed gun

A good way to get loads of abuse from passing motorists.

16 minutes ago, pcaouolte said:

A good way to get loads of abuse from passing motorists.

After theyve gone home to change their underwear first, realising they've got a letter coming 😉

Sat Nav speed should be accurate and, as said speedos are set 2 or 3 MPH low  Edit Ooops, High

Edited September 4, 2025Sep 4 by Shearers

24 minutes ago, Shearers said:

are set 2 or 3 MPH low?

Speedo's are always set high. They always show that you are travelling faster than you actually are.

1 hour ago, pcaouolte said:

haven't yet had a speeding ticket in 45 years of driving.

You're about due then. I got to 46! (Technically nearly 50 if you count motorcycling first).😀

12 hours ago, Eric Bloodaxe said:

You're about due then.

It's mainly down to luck. I've had some close calls. I will always remember my first one on a motorcycle when the police used to stand on the side of the road doing speed checks and stop you when you got to them if you were over the limit. I was (slightly?) exceeding a 30mph limit on the bike when I spotted the speed check. I pulled into a random driveway on the side of the road before I got to them, waited there for a little while and then pulled out of the drive and went back the way that I came so that I never passed the police. Never heard any more about it. 😀