There are various track sizes and quantities of cars available on a dodgems track. As a general rule you should be looking for a ride with 14-16 cars. This an ideal number for virtually any event. Much less and you end up with endless queues for the rides, much more and you have a traffic jam that would put the M25 to shame.
Beware some operators who offer suspiciously low quotes to rent bumper cars, a favourite trick is to advertise a price much lower to win the job. When your dodgems turn up, they have no roof covering (no good if it rains), no lights or music.
When you complain you will be told that you have hired the cheapest option. These things can be added back on to your package, but you will be charged extra for them, and may end up paying more than you would have done if hiring a 'complete' ride in the first place.
A word about the name, the industry name for this type of ride is dodgems, and alludes to the fact that you are supposed to dodge the other riders. Most of the U.K. sticks to this name, except in the North East of England. There for some reason the rides have always been known as "Bumper Cars".
There are 2 basic types of bumper carz available.
Continental Track
Tending to be moderner, with superior sound and lighting systems, and more decorative artwork. Supplied on a trailerised system that folds out in situ, these look more impressive than the regular rides, but need to be driven into position, they cannot go over walls, through narrow gates or around really tight bends.
Traditional Type Track
These are the original type ride, not as ornate or visually exciting as the modern counterpart. Their big advantage is the fact that they entirely dismantle so can access venues impossible for their larger cousins. Also if you are having a vintage or retro themed event, they may be a better fit.
rAn Example Of One Of Our Modern Dodgem Cars