aggressive drivers don’t save time

exilegareth wrote:

My daily commute to work is 60 miles up the A1 in Northumberland.

This morning a police car overtook me on the last stretch of dual carriageway, about twenty miles before Berwick. (Yes, I know it’s the main road from England to Eastern Scotland, but big chunks of it aren’t dual carriageway and feature all manner of scary junctions.)  

I didn’t follow the police car, and tucked in behind a hatchback driven by an old man in a cap. He stuck to 50mph all the way, and I sang along to the CD player. The police car vanished off into the distance, so that even on the long straights I couldn’t see him in front of me.

On the way down the hill into Berwick, who was two cars in front of me? Yep, the police car that passed me twenty miles before…

This is normal for my drive to work, and home. Doesn’t matter if I speed or not, th e time it takes is decided by things I can’t control, like whether there’s a tractor in front of me on one of the single carriageway stretches or not.

Whilst out of sight the police had carried out one speeding stop, two pee stops and a coffee/donut stop. Thus being more productive with there time.

My daily commute to work is

My daily commute to work is 60 miles up the A1 in Northumberland.

This morning a police car overtook me on the last stretch of dual carriageway, about twenty miles before Berwick. (Yes, I know it’s the main road from England to Eastern Scotland, but big chunks of it aren’t dual carriageway and feature all manner of scary junctions.)  

I didn’t follow the police car, and tucked in behind a hatchback driven by an old man in a cap. He stuck to 50mph all the way, and I sang along to the CD player. The police car vanished off into the distance, so that even on the long straights I couldn’t see him in front of me.

On the way down the hill into Berwick, who was two cars in front of me? Yep, the police car that passed me twenty miles before…

This is normal for my drive to work, and home. Doesn’t matter if I speed or not, th e time it takes is decided by things I can’t control, like whether there’s a tractor in front of me on one of the single carriageway stretches or not.

PRSboy wrote:

wellsprop wrote:

PRSboy wrote:

alansmurphy wrote:

wellsprop wrote:

It’s a really interesting mathematical problem, this…

 

hence why my average speed on my drive to uni is 7mph and the average on my cycle is 17mph (even though the commute takes me the same time overall).

 

 

Interesting or wrong?

Presumably the cycle average speed is based on moving time only.

It’s moving time only for both. The overall elapsed time is 1 hour for both.

It’d be much easier to explain in terms of velocity distribution plots, but I don’t have that for the drive.

Still don’t get it.  Assuming the distance is the same, the overall elapsed journey time is the same, and basis of calculation the same, then surely the average speed cannot be different.

Yep, I got it the wrong way around! Oops.

It’s way easier to explain in terms of velocity distribution and quartile speeds.

I’ve realised I don’t mean “average” speed, I mean quartile speeds. When cycling, the standard deviation of my velocity distribution is much smaller than it is when driving.

I.e. I spend a very long time sat stationary when I drive my commute, but when I’m moving, I’m travelling a lot faster than when cycling. Strava just spits out my cycling data in terms of moving speed.

I’m interested in how a

I’m interested in how a journey with an average speed of 7mph takes the same time as one at 17mph…

alansmurphy wrote:

wellsprop wrote:

It’s a really interesting mathematical problem, this…

 

hence why my average speed on my drive to uni is 7mph and the average on my cycle is 17mph (even though the commute takes me the same time overall).

 

 

Interesting or wrong?

Presumably the cycle average speed is based on moving time only.

Was overtaken yesterday
Was overtaken yesterday whilst doing 27mph in a 30 zone. Despite 3 mini rounabouts and 3/4 mile I arrived at their turning off point 2 car lengths behind but ultimately they delayed my journey by a few seconds as i had to give a gap after they’d overtook and then slowed more at the right turn at the roundabout.
That is obstruction right right there, one which a Met nobber accused a cyclist of doung after forcing him to stop after illegally speeding and close passing him first.
When motorrists push past and indeed dangerously I just want to give them a hard slap, plod don’t give a fuck about such driving std, they don’t see/won’t accept that that is how deaths and serious injuries occur and just let it slide.

It’s a really interesting

It’s a really interesting mathematical problem, this. In very simplistic terms, there are a number of discrete speeds at which you can travel through a city without having to stop at a red light (and therefore nullifying any gain due to speeding).

I took a stab at trying to calculate the average speed required to get between traffic lights without having to stop (on my commute through Bristol city centre). To calculate this, you need to know how long the traffic lights are green for and how long they are red for, as well as the distance between two sets of lights.

Generally, the speed at which you want to travel is a function of the period of the traffic lights changing colour. This is why sometimes you always get a green light and sometimes you always get a red light. And, interestingly, the speed at which you need to travel to match that period is around 10-15mph (at least for the roads I was looking at).

Which kind of matches with my cycle commute through the city, cars overtake me where they can, then I just leapfrog them as they are queuing for a traffic light, which turns green shortly before I get to it very often.

Cars then get really stuck if there’s so much traffic that they have to wait for a couple of cycles of traffic lights – hence why my average speed on my drive to uni is 7mph and the average on my cycle is 17mph (even though the commute takes me the same time overall).

Oh, I don’t know. On a recent

Oh, I don’t know. On a recent journey, our taxi driver shaved a good hour off the journey with a combination of assertiveness, creative use of what passed for the pavement, sheer bloody minded-ness and not giving much of a toss about oncoming traffic.

That was over 200km and in Nepal, though, so normal rules didn’t apply 😀