Having a car in Adelaide is a real asset. You can park easily enough in the CBD and a car also allows you to visit other nearby towns and suburbs which may be of interest.
Adelaide being a wine lovers paradise does mean you may rely on taxi's anyway, but if you have days when drinking isn't on the agenda a car will serve you well. There are some nice beaches down south and also Victor Harbour. You can visit the hills and Harndorf. The wine regions are also most easily reached by car.
Firstly, there are a lot of traffic lights that have a nasty habit of turning yellow just before you reach them, meaning you have to wait a full cycle. During the daytime on a weekday most traffic lights you approach will be red but at night time most of them will be green, providing a lone car ahead doesn't activate the pressure sensor and switch the light to yellow just as you approach it...
Secondly, the on-road culture is a bit harsh (I asked my dad about this who said that things have deteriorated as more and more cars are added to the existing roads). The drivers tend to be polarised into two communities, those who I call "speed freaks" who dart around betweeen lanes, tailgate and speed off quickly, and the "slow coaches" who putter around at 10km/h under the speed limit and give no heed to their surroundings. Either alarming or frustrating.
Adelaide has no freeways leading into the city centre, a lot of main artierial roads are 4-lane (two in either direction) leading to heavy traffic during peak times and longer-than-expected journeys. Travelling the 12 km's betwen Glenelg and the city is no hassle (traffic lights aside) as it has 6 wide lanes (3 either way).
Keep in the left lane unless you intend to travel over the speed limit, be wary of going more than 10% over the speed limit (eg. 66Km/h for a 60km/h zone) on main roads as you can get caught by speed cameras, leading to fines over A$150.
On main roads, get into the leftmost or rightmost lanes well in advance of making a turn as a closely packed line of cars can form, meaning you either have to miss the turn or squeeze yourself in with only centimeters to spare.
Driving yourself around is definitely the way to get around Adelaide. Public transport is sketchy at best, and most of Adelaide's sights are spaced apart, or the sort of thing where you want to stop at one place for a few minutes, drive a little way on to the next, stop there for a couple of hours... if you add waiting for almost non-existant buses to that list, you'll spend half your day waiting at metro stops! Also, there are good day trips that are difficult/expensive to do if you don't drive yourself.
Driving in Adelaide is fairly low-stress; the traffic is orderly and not congested, except on some roads in peak hours (8-9am; 5-6:30pm). Parking is generally easy to find everywhere you go - though in the CBD during business hours, you'll usually have to pay for parking; if you're going to the city, public transport might be better, since the CBD is one place where you *can* easily get transport to.
The only downside to driving in Adelaide (apart from rising petrol prices) is that the quality of signage in the suburbs is variable. Sometimes streets are clearly marked, and routes (eg, go down this road to get to this suburb), other times, you're on your own. Even in the city, you're sometimes sitting at the traffic lights squinting down the street trying to find out where you are! In the hills it tends to be easier to find your way around without a street directory.
Here are some general road rules.
Unlike some Aussie states, you can't do a u-turn at a traffic light.
Always give way to the right.
Do heed speed limits, and keep your eyes open because they change regularly. There *are* speed cameras around and speeding fines are quite stiff. If you see oncoming cars flash their lights at you, they're usually warning you that there's a speed camera ahead.
You can turn right at traffic lights if the arrow light is green (obviously), but also if main light is green while the 'arrow' light next to it is blank, or if the main traffic light is green but there's no arrow - in those cases, drive out into the intersection ready to turn as soon as there's a break in traffic.
Annoyingly, buses have the right of way. This means that if a bus in front of you is indicating to pull out onto the road, you have to stop (if safe), or change lanes to get out of its way, otherwise they *will* swerve into you!
Be aware that as of a couple of years ago, the default speed limit is 50. Main, 'arterial' roads are 60, but all side-streets and all streets in the CBD are 50. 50 zones usually aren't specifically marked as such, so you have to assume that unless there's a sign telling you otherwise, you should do 50 - sometimes what looks like a main/arterial road, isn't 60!
In some countries, you can drive dangerously, swerving into oncoming traffic and swapping lanes without warning, and everyone will react accordingly because they expect people to drive like that and are on their guard. In Adelaide, if you drive like that, you will crash! Indicate, and leave enough space for other cars!
Adelaide is a long way from anywhere, so be sure that you are accustomed to driving long distances if you do choose to drive there. This photo was taken on the road from Sydney to Adelaide - you do pass through many landscapes, including mountains and river valleys, but the majority of the trip is spent corssing vast desolate plains where there is little settlement - but this can be quite relaxing and unusual for most visitors.
Our car was the best way for us to get around, but there are heaps of bike tracks and walking tracks if you'd rather get around that way. There are also a couple of free bus services in the centre of town.
Driving in Adelaide is very easy. The roads are very open and the traffic is quite light compared to other capital states in Australia.
With only two highways in Adelaide it is quite easy to get back on track if you make a wrong turn.