Because scooters are really designed for outdoors, and are usually used outdoors, there are some serious safety issues. Not all these safety issues are due to the nature of the scooter design and function; some are behaviour issues with the user. I'll try and cover all the issues I've come across over the years but users always seem to come up with new ways to have accidents. I'll begin with design issues and work my way into behaviour issues.
1) Scooters are tippy. Four wheeled scooters aren't as tippy as three wheeled scooters but both have a high center of gravity and are prone to tipping if they are driven across the side of a hill or ramp, or if the user drives too close to a sidewalk curb and the wheels on one side slip off the sidewalk. Users should always drive up or down hills and stay well back for drop offs like curbs, cliffs and as one of my clients found out, docks.
2) Scooters behave like cars when on slippery surfaces. If the user tries to travel across a terrain that's too snowy, or too soft such as sand, it's likely to get stuck. Also, if the scooter is travelling down a steep hill that's covered with ice, there isn't much chance of stopping at a stop light, driveway or crossroad. Cars aren't safe if they are driven on improper terrain or icy surfaces and neither are scooters.
3) Most scooters have air filled tires and will go flat if driven across a nail, tack or broken glass. On the up side scooter tires have tubes in them which can be repaired with a bicycle tube repair kit. Air pressure is important on scooters just as it is on a car. If the tires are too soft they will wear out quickly and run down the batteries prematurely, reducing the range of travel.
4) Scooters are small and hard to see on the road. I ride a 975 lb., 5 foot tall, 9 foot long, 3 1/2 foot wide motorcycle for fun and cars don't see me in spite of the fact my lights are blazing whenever the bike is running. Scooters are 3 feet high, 4 feet long and 2 1/2 feet wide and usually have lousy, if any, lights. Users should expect that they aren't seen by cars and trucks; especially in parking lots.
5) Users don't always realise the scooter is not a car. Scooter users are still pedestrians and should behave like pedestrians by riding on sidewalks whenever possible.
6) Driving drunk on a scooter is safer for everyone than drunk driving in a car, except the scooter driver. Inebriated people lose co-ordination, inhibitions, common sense and balance. They shouldn't be on a scooter any more than they should be in a car especially when you consider some people are in a scooter due to drunk driving.
7) Aggressive driving and bad temper is a problem with some users. Although small, scooters can seriously hurt other people, furniture, televisions, pets and other stuff. People who don't drive with care and control their temper usually lose their right to use their scooters, or worse. I have one client who is not allowed in our local department store because he used to knock over displays at the slightest provocation.
8) Over confidence is an issue with some people. This is especially true when someone upgrades from a three wheeled to a four wheeled scooter. People who believe their scooter, or their ability to drive their scooter, is better than it is, are going to find out eventually that they may be mistaken and possibly get hurt.