Its for my GCSE electronics project and i want to make one for under 5 quid how? :?:

 

For a start this board is populated by people from all over the world, so most members probably won't know what a 'quid' is. It's also helpful if you fill your location in, so people know where you're from (UK, or England, or Scotland etc. is all you that need to enter).

Five UK Pounds isn't very much, what sort of display were you thinking of?. Presumably you will need at least 4 digits, two for each lane, so that's at least four 7-segment displays, and drivers for them, plus counters and some type of detector for the cars.

If your school has PIC programming capability, you could simplify the design a great deal, to just the PIC, the displays, and a handful of small components (at the added work of writing the software) - using an LCD text module would make it even easier, but at more cost.