Why do some races finish at the beginning of the pit straight?

[Watters92]

Hi guys, gals and everything in-between!

My friend has broken my brain by asking why some races start at the start line but finish at the beginning of the pit straight (the back of the grid).

For example, Shanghai, Silverstone, Austin and Spa all finish at the end of the last corner rather than the start line.

I'm hoping someone has at least a theory about this!

Many thanks in advance

[DiogoBrand]

I'm curious about that as well. At Silverstone for example AFAIK they have a ridiculous speed limit and an endlessly long pitlane to keep people from doing their fastest laps while entering the pitlane, when they could solve this simply by moving the finish line further ahead.

[Dazed1]

My theory is that's where the guy with the flags is.

[astracrazy]

I believe its to do with the race control location - it has to be level with the finish/timing line. Why? In case the timing system breaks they can log the cars.

If we take the last race, Canada, the start and finish line is together and level with the end of the pit garages. So i would assume this is where race control is.

If race control is the opposite end of the pit garages (the start) then that's where you get what you mentioned and so the start line obviously has to be moved forward to a point where all the grid positions are on the main straight.
Look at race track maps of the ones you listed above against others and you will see the finish or start/finish is level with one end of the pit garages.

Thats how I understand it, but I could be totally wrong.

[i70q7m7ghw]

I think it's more case of offset starting formations rather than two independent start & finish lines. At some tracks, the position of the finish line doesn't give enough room for the grid to form up without curving around a corner so they shift the starting grid forward to fit everyone in. This just means at some tracks they start ahead of the line, at others they start before it.

[TzeiTzei]

My memory is hazy... but I think that the start finish line (not the grid) has to be either before or after the pitlane. It can't be in the middle of the pit lane. Now of course someone comes and gives an example where it's right in the middle. But like I said, my memory is hazy...

[PlatinumZealot]

Yeah a bunch of tracks have it in the middle!

[Big Tea]

Is it no literally, because thats where the timing triggers?
I know we then have the problem of why they are there, but that could be simple tradition for that track?