Lights, panels and pit exit signals
Flags are only part of how race control talks to drivers. F1 also uses lights on the start gantry, electronic light panels all round the circuit, a display in each car's steering wheel and a set of lights at the end of the pit lane. Under the F1 sporting regulations, a signal on a trackside light panel or on the car's dashboard has exactly the same meaning and force as the matching flag.
The start lights
The race start is signalled by five red lights on a gantry above the grid.
- Once every car has stopped in its grid slot after the formation lap, the panels on the grid flash blue for 5 seconds and the gantry shows "Pre-Start".
- The five red lights come on one at a time, one second apart.
- After the fifth light comes on, there's a pause. Its length is chosen by the starter, so drivers can't guess it.
- All the lights go out together. That's the start: "lights out and away we go".
If a car moves before the lights go out, it's a jump start, which the stewards punish with a time penalty. See the race start.
When the start doesn't go ahead
The gantry also has orange lights for when something goes wrong.
- Extra formation lap: orange lights and a board saying "EXTRA FORMATION LAP". The green lights then come on after 2 seconds and the field goes round again. This happens if, say, a car stalls on the grid. The race is shortened by one lap.
- Aborted start: orange lights and a board saying "ABORTED START". Everyone stays in their grid slot and the start procedure begins again from the 10-minute signal. The race is shortened by one lap for each aborted start.
Green lights on the gantry also start the formation lap.
Trackside light panels
F1 circuits have electronic light panels at the marshal posts. They show the same signals as the flags (yellow, double yellow, green, blue, red and so on) and also "SC" and "VSC" when the safety car or virtual safety car is deployed. Panels are brighter than flags, which helps in bad light, rain and at night races.
The marshals still wave flags as well, so there are always two ways for a driver to see a warning. The track is divided into marshalling sectors, each running from one light panel to the next. The rules on slowing down under yellows, and the minimum times under the safety car, are all worked out per marshalling sector.
The steering wheel display
Each car has a standard FIA electronic control unit that sends race control's signals straight to a set of lights and messages on the driver's steering wheel. When a yellow flag comes out ahead, a light on the dashboard comes on before the driver even reaches the marshal post. Messages such as "VSC ENDING" or "LAPPED CARS MAY NOW OVERTAKE" also go to every team through the official messaging system.
The pit exit lights
At the end of the pit lane there's a red light and a green light. Cars may only leave the pit lane when it's green. Crossing the line at the pit exit on a red light is a serious offence and usually brings a heavy penalty.
The pit exit is closed (red) during a red flag, and for parts of a safety car period while the queue of cars passes the pit exit.
A blue flag or flashing blue light at the pit exit warns a driver who is rejoining the track that cars are approaching at racing speed. The driver has to rejoin carefully and must not cross the white line that separates the pit exit road from the track.
Lights on the cars
F1 cars have a red light at the back. It must be switched on whenever the car is on intermediate or wet tyres, so the driver behind can see it through the spray. If the main rear light fails, race control can call the car in until it's fixed.
During testing, a car driven by someone who doesn't hold a super licence must show a blue rear light, so other drivers know to give it extra room.
The safety car has orange lights on its roof. When they go out, it's the signal that the safety car will come in at the end of that lap. See the safety car.