TDF - Elimination times
 

Can someone explain how elimination times are arrived at for stages of the TDF. My understanding is that riders must finish within a certain time which is made up of the winning time plus a percentage and that the percentages vary depending on the difficulty of the stage.

Who decides the percentages and how are they applied.

Often it's 10% of the winner's time, but that might not be true on a tough mountain stage. Also, if a rider gets into the "autobus" he's pretty safe even if it's outside the limit as they won't eliminate an entire pack of riders.

It's in the rules. Link from the official TDF web site.

Here's the text. It is followed by a table that doesn't display well here:

ARTICLE 22
PERMITTED FINISHING TIMES
According to the types of stages and their level of difficulty, permitted finishing times vary according to the application
of the following coefficients:

Coefficient 1
(stages with no particular difficulty) The permitted finishing time is calculated according to the winner’s finishing time plus:
4% if the average speed is less than or equal to 36 km/h;
5% between 36 km/h & 38 km/h;
6% between 38 km/h & 40 km/h;
7% between 40 km/h & 42 km/h;
8% between 42 km/h & 44 km/h;
9% between 44 km/h & 46 km/h;
10% between 46 km/h & 48 km/h;
11% between 48 km/h & 50 km/h;
12% over 50 km/h.

Coefficient 2
(stages presenting medium difficulty) The permitted finishing time is calculated according to the winner’s finishing time plus:
6% if the average speed is less than or equal to 35 km/h;
7% between 35 km/h & 36 km/h;
8% between 36 km/h & 37 km/h;
9% between 37 km/h & 38 km/h;
10% between 38 km/h & 39 km/h;
11% between 39 km/h & 40 km/h;
12% between 40 km/h & 41 km/h;
13% between 41 km/h & 42 km/h;
14% between 42 km/h & 43 km/h;
15% between 43 km/h & 44 km/h;
16% between 44 km/h & 45 km/h;
17% between 45 km/h & 46 km/h;
18% over 46 km/h.

Coefficient 3
(stages presenting intense difficulty) The permitted finishing time is calculated according to the winner’s finishing time plus:
7% if the average speed is less than or equal to 30 km/h
8% between 30 km/h & 31 km/h;
9% between 31 km/h & 32 km/h;
10% between 32 km/h & 33 km/h;
11% between 33 km/h & 34 km/h;
12% between 34 km/h & 35 km/h;
13% between 35 km/h & 36 km/h;
14% between 36 km/h & 37 km/h;
15% between 37 km/h & 38 km/h;
16% between 38 km/h & 39 km/h;
17% between 39 km/h & 40 km/h;
18% over 40 km/h

Coefficient 4
(short stages presenting intense difficulty) The permitted finishing time is calculated according to the winner’s finishing time plus:
9% if the average speed is less than or equal to 30 km/h
10% between 30 km/h & 31 km/h;
11% between 31 km/h & 32 km/h;
12% between 32 km/h & 33 km/h;
13% between 33 km/h & 34 km/h;
14% between 34 km/h & 35 km/h;
15% between 35 km/h & 36 km/h;
16% between 36 km/h & 37 km/h;
17% between 37 km/h & 38 km/h;
18% between 38 km/h & 39 km/h;
19% between 39 km/h & 40 km/h;
20% over 40 km/h

Coefficient 5
(individual time trials):
The permitted finishing time is calculated according to the best time plus 25%.

Coefficient 6
(team time trials):
The permitted finishing time is calculated according to the best time plus 25%
(time calculated on the fifth racer of the winner team, increase by 25%.

Elimination coefficients
Finishing times may be adapted under exceptional situations (weather conditions, blocked roads, serious accident
or incident, etc.) according to the assessment of the stewards committee, with the agreement of the race management.
If the percentage of eliminated riders rises above 20% of starters in the stage, permitted finishing times may
be increased upon the decision of the stewards committee, with the agreement of the race management.
It is understood that the riders who finish within the new permitted times will qualify for following stages, without
a precedent being set for the rest of the race.

Possible exceptions
The stewards committee may exceptionally allow one or several particularly unlucky riders to qualify, after informing
the race management. In this case the following factors will be taken into consideration:

The average speed of the stage;
The point at which the incident or accident occurred;
The effort made by the rider or riders delayed by such incidents or accidents;
The possible degree of impassability of the roads.

As these finishing times are calculated in relation to the winner of the stage, disqualifications resulting from the
decisions once taken by the stewards committee and made available thereafter cannot in any case give rise to an
entitlement to any exception for any rider.

What is the lowest amount of people at the end of the TDF?

Probably the 22 remaining from the 60 starters in the first Tour.

That's good info Zorro, thanks.