Below is a list of what fleet drivers could include in such a kit:
Reflectors or Flares – If the vehicle breaks down, it is important to ask for help the soonest possible and also warn other motorists, especially if the vehicle is immobilised at a dangerous spot and cannot be moved until road assistance (or a crane) arrives.
Sturdy Scraper, Snow Shovel, and Snow brush – Winter storms may result in unexpected road closures, which means that motorists may need to remain in frigid temperatures for hours. It is paramount to help clear snow while waiting so that it doesn't build up. A de-icer can also help too. And, don't forget to clear the snow and ice from lights and mirrors too.
Screenwash & Demisting Pads – It is critical the driver has full visibility through all glass panels on the vehicle. According to the Highway Code, it is against the law to drive with snow on the car (the law also dictates the driver demists all windows before they set off). Also, use a good quality screenwash (keep a spare one somewhere handy too) that can protect the vehicle down to, at least, -35. This will help prevent the water from turning into ice. In any other case, the windscreen wipers might be rendered useless in extreme cold.
Lock De-Icer – More than often, vehicle locks get frozen in winter weather and are too difficult to clear so you can unlock the vehicle. Spray de-icer into the lock or try warming the key. Alternatively, you could use an oil-based lubricant to help unfreeze the lock.
Torch & Reflective Triangle and Vest – Carrying a torch with you will help you find your way in the dark, should the vehicle breaks down at night at an area that has no or low light. It will also help others find you in the dark (for the same reason, it is wise to have a Hi-Vis vest and a reflective triangle with you too). Make sure you also have an extra set of batteries. Or you could take a wind-up torch instead.
Jump Leads – Winter is a common time for vehicle batteries to die. If your battery fails, you need to have jump leads to help revive it.
Radio – If there are any emergency broadcasts, you need to make sure you have listened to them on time. Prefer a battery-powered radio or a wind-up model.
Square of Carpet – If you get stuck in the snow, put this under your drive wheels.
Vehicle tracker - if you do get lost in the snow on business, having a vehicle tracker fitted could be a life saver. If you're driving in remote areas, the GPS tracker can relay your position to the office and emergency services.
First-Aid Kit – It could save your life (and/or the lives of your passengers) in an emergency.
Jack & Tyre Iron (aka Lug Wrench) – If you have a flat tyre, you will need them to remove the lug nuts that hold the wheel on and change the tyre.
Extra Food & Water – Non-perishable food (i.e. meals ready to eat – make sure you rotate them out regularly) and some water will help you get energised and hydrated.
Extra Clothing & Survival Blanket – If you get down to the snowy road (i.e. to change a tyre or fix the vehicle), you need to have clean, dry clothes to slip into right after (including mittens and boots) so you don't suffer from hypothermia. A survival blanket is a multi-purpose item that will not only keep you warm but help treat victims in shock. They don't take up too much space and can be life-saving indeed.
Other things you could include:
A pair of pliers, socket set, and a small wrench set
A few screwdrivers, a tyre pressure gauge, duct tape, and spare fuses.