The first two minutes matter most
Before diagnosing anything, make the car safe. Get it as far off the carriageway as you can manage, switch the hazard lights on immediately, and place the warning triangle well back down the road, considerably further than feels necessary at speed. On a highway, that means a hundred metres or more so approaching drivers have time to react.
Then get everyone out of the car and behind the barrier, on the side away from traffic. This is counterintuitive, because the car feels like shelter, but a stationary vehicle on the shoulder of a highway is one of the more dangerous places to sit. The exception is dense, slow-moving city traffic with nowhere safe to stand, where staying belted in is the better option.
Only once that is done should you work out what is wrong. Note the location precisely before you call for help, because the single most common cause of a long wait is a vague location. A highway kilometre marker, an exit number or a dropped map pin turns an hour of searching into a direct approach.
Judging whether it is drivable
Some faults leave you a limited amount of safe driving; others do not. Overheating is the clearest do-not-drive case. If the temperature gauge is in the red or steam is coming from the bonnet, continuing will warp the cylinder head, which converts an inexpensive hose failure into an engine rebuild. Stop, switch off, and wait for it to cool before doing anything else.
A red warning light generally means stop; an amber one generally means investigate soon. Oil pressure and battery charge lights are the two that warrant pulling over immediately. Losing oil pressure destroys an engine in minutes, and a charge failure means you are running on battery reserve and will lose the ignition entirely, quite possibly at an inconvenient moment.
Brake and steering faults are never drivable. A pedal that goes soft or sinks, a steering wheel that suddenly feels loose, or a loud knock from a wheel are all reasons to stop where you are rather than pressing on to the next town. So is a burning smell, which usually means something is overheating badly enough to be a fire risk.
What roadside assistance actually covers
Assistance divides into two categories, and the difference matters when you call. On-the-spot repairs are minor fixes done at the roadside: a jump start, a tyre change, fuel delivery if you have run dry, or a lockout. These resolve most calls and are quick.
Towing is what happens when the fault cannot be fixed there. Cost depends on distance, vehicle weight and whether a flatbed is required. A flatbed is necessary rather than optional for all-wheel-drive cars, for automatics in many cases, and for any car with damaged steering or a seized wheel, because towing those with wheels on the ground causes further damage.
If your car is under manufacturer warranty, roadside assistance is very often already included for the warranty period, and many comprehensive insurance policies include it as an add-on. It is worth checking what you already have before paying separately, because a large share of people pay twice for coverage they hold and have forgotten about.
Avoiding the call in the first place
The great majority of breakdowns are not sudden. Battery failure, overheating from a slow coolant leak, and tyre blowouts from chronic underinflation all give weeks of warning to anyone looking. A five-minute check every couple of weeks, covering tyre pressures, coolant level, engine oil and how eagerly the car starts, removes most of the risk.
Before any long drive, extend that to a proper look: tyre tread and pressures including the spare, all fluid levels, wiper condition, and every exterior light. The spare is the one people discover has been flat for two years at precisely the wrong moment, and on cars supplied with a repair kit rather than a spare, check that the sealant has not passed its expiry date.
Keep a basic kit in the boot. A torch, a power bank, jump leads, a warning triangle, a reflective jacket and a litre of water cover most situations, and the water serves both the radiator and the people waiting beside it. None of it is expensive, and it converts a stranded evening into an inconvenience.
