So, they list vehicle acceleration as either "walking" or "running" and say you can make tests to speed up (with 'speed' being the safe maximum).

Great, but other than making those tests to speed up, does the vehicle gain speed on its own? Take, for example, the Bulldog Step-Van with "acceleration" 5/10

With its 2 pilot, and a maneuver autosoft of 2, it gets 4 dice to drive itself around. Let's assume it buys one success with that. It can "run" down the street at 15 meters per turn (5 m/s ~ 11 mph) ... you'd get pulled over for going too slow!
Even if it used all three of its actions per turn to speed up, it'd only be going 25 meters/turn or about 18-19 mph.

That can't be right. It'd take an ace-rigger just to take that thing on the highway.

But, if you can "accelerate" by 10 meters EACH combat turn, that would make a lot more sense, but make the lousy 4 dice it gets for "hauling ass" somewhat dwarfed by the speed it gets on its own - moreso for faster vehicles like the eurocar westwind, which would gain 60 meters/turn and would get on average 2 hits to drive itself around (an extra 10, yay)...

Anyone had to run a vehicle-combat yet and figure all this out? o.O

By the looks of it, combat will be over before my players pull out of their parking spot.

you have to realize that its able to accelerate between 5-10 mps per second so base would be 5-10-15 for a total of 30 meters in a 3 second combat turn, meaning that in a full minute of standard acceleration you would reach roughly 5miles traveled in one minute which is about 30 mph which is about right.

at maximum accel of 10mps, one minute of acceleration puts you at roughly 10miles traveled and max speed reached in under a full minute of acceleration

That makes more sense - but does it say anywhere in the BBB that the "acceleration" is in meters per second as opposed to meters per turn?

Cruising speed for KM/Hour would be calculated with the following formula:

(((Speed/3) x 60) x 60)) / 1000= KM/H

The Honda Spirit for example would have a maximum speed of 96KM/H

Acceleration would easiest be calculated by using the same formula.

The Honda Spirit would then have an effective acceleration of between 0-24KM/H

Let's assume it can accelerate by the runspeed each turn without any roll. The rating is called "acceleration", and the test is optional, after all. It's not that hard to press a gas pedal either. Getting that extra little acceleration out of it should be hard. As should staying on the road if all you do is floor it without mercy.

Let's take a very fast car as a benchmark for testing the viability of this rating: the Eurocar Westwind. Acceleration 20/60. Starting out at 0 km/h, I will try and calculate the time it takes to reach 100 km/h (approx. 62 mph).

If I'm not mistaken, multiplying meters per turn with 1.2 will give the speed in km/h. This is because one hour is 3600 seconds, one kilometer is 1000 meters and one combat turn is 3 seconds(3600/1000)/3=1.2. So 60 mpt = 72 km/h. In 3 seconds the car has reached 72 km/h. In 6 seconds the car has doubled that speed, and is now traveling at 144 km/h. 100 km/h is reached approx. in 4 seconds. That rivals most race cars today. It's the same spec that the Ferrari F430 is presented with. But those specs are not casualy reached, while the Westwind would do this every time, without a test, at least on a straight road. Let's say you made a test to accelerate, getting 4 hits. Then you would reach 100 km/h in barely more than 3 seconds. This all makes sense, because it fits with how top speeds of vehicles in Shadowrun relates to today's cars.

PS. Maybe now you can see why the speed increase you gain from the roll as opposed to the normal acceleration is so small? It's no small feat to press a race car down from 4 to 3 seconds time from 0-100 km/h.

Would someone care to post the page numbers with the logic that goes along with "default" acceleration vs. rolled acceleration? (I've loaned my books out so I can't do it myself and I want to review this later)

As far as I can tell reading through everything, you automatically go the running speed by spending a free action. Though, in occurrences where the full speed of various vehicles was being used, I'd switch over to Chase Combat rather than Tactical, and the comparative speeds isn't quite as critical.

Mintcar--I'm not disagreeing that your way is more in line with real world cars and physics. It would seem that the only time the argument comes up though is when the runners are trying to stop someone else from getting away or vice versa. Basically, this is the scene where the bad guys piles into the car and the good guys unload into the car and gun it down before it gets around the corner.

Once both teams are in vehicles, then you switch over to Chase combat and you get the prolonged car chase with people leaning out windows to shoot at each other.

IMO--The game designers realized that it would be difficult to create any balance of speeds between people and vehicles so they did their best with the tactical system and offered a separte system for exclusive use with vehicles. I find the wording a little difficult to understand with the Chase system (the break down between a Chase Turn and an Initiative Pass) but I'm working my way through it.

i never understood the problem people had with SR3 vehicle rules. two of the numbers where static, period. one changed when the GM wanted it to change. add those up and you had a partial score. then slap the riggers dice outcome on top of that and presto, your done for that combat turn. unless you want to do some fancy moves that is.

still, i have yet to see, much les read, the full text of the SR4 rules so how it stacks up to the SR3 rules i cant realy comment on.

my problem is the the vehicle design (not customization so much, but design) they dedicate 1/4th of a book to everything, but the first sentance basicaly says "yea, we're giving them to you,b ut you shouldnt design indivual cars, or lets characters build a car from scratch with these rules."

My players came up with a clever solution to what they thought was inadequate vehicle speeds. Air elemental's movement power... which seems to target vehicles just fine (as far as I could tell) and pushed the van from 22 mph to 110 mph in 1 second. The crash was spectacular.

Damn you GM Blackhat, damn you! I would never has asked the spirits to speed us along if I had known the rigger had not read the ramming rules.

Hee. Style, you should have remembered to ask/tell the spirit for a Guard service first.

Yeah, spirits are tons of fun in conjunction with vehicle combat. It's apparently just fine by the RAW to keep the spirit inside the vehicle (therefore physically manifest and able to keep pace to the vehicle without trying). Guard, Movement, and if you have an extra service laying around you may as well Conceal too.

i have allways interpeted spirits as only being able to do one service at a time. as for a new one, the old is dropped...

as for a spirit keeping up with a vehicle under effect of movement. i dont recall, but i think the speed of a spirit, even while manifested, can be quite high...

However, this experience has taught our group two things: 1) Get your own vehicle. 2) Spirit Accelerated Drone-Vehicles are amazing weapons.

BTW, the movement powers could affect anything no check since at least SR2. Go figure.