I'm not understanding the vehicle combat rules more specifically the Acceleration rules. I don't exactly see how they affect anything because it says you can make a Vehicle Test and each success adds an additional 5 meters to the movement rate but doesn't say it can only gain speed up to the Acceleration movement rate. So if you've got and elf on a rapier bike and a troll in a mac truck and they both score the same number of successes then they both gain equal acceleration even though we all know a rapier would leave the truck in the dust. So it seems that the acceleration rating does nothing???????

Also it is listed as having a walking and running rate but if your speed on a rapier is a 120 (probably faster but just for an example) and the acceleration is 25\50 (also just for example) how does that calculate into the speed exactly.

Honestly, the rules are really unclear. As is, either the Top Speed means nothing, or Acceleration means nothing. I would do it like this, though: assume that acceleration is how much you can increase your speed in a turn. So, if you're stopped in a vehicle with 25/50 Acceleration and a Top Speed of 150, you can go up to 50 meters on the first turn the vehicle moves. If you go more than 25, you count as 'running', which gives some bonuses (+2 to defense rolls) and some penalties (-2 to ranged attacks). Next turn, you can go the same distance, and increase it by up to 50. Again, if you increase it by more than 25, you count as 'running'. And so on. Speed is the maximum. (Though I think the book vaguely mentions that you can go faster at significant penalties.)

That seems the easiest way to run it.

When actually using the chase rules, none of this matters, because of the abstraction of movement and location. (Though the chase rules are rubbish, in my option.)

I've actually found the chase rules to be pretty helpful in running chase combats and I'd highly recommend it. Honestly, I've found that if there is one vehicle going at speed then there are usually several vehicles going at speed.

I use the acceleration when I am running a vehicle in personal combat (which is rarely--see above). Basically it tells me how far a drone can "walk" and "run" each turn. Make piloting checks to go faster than that like a "sprint" action to a maximum equal to speed.

I only use speed as an abstraction in chase combat and only for the ramming rules. Pursued can go this fast, pursuers can go this fast. This means this much damage. I may give a PC a bonus if he is in chase combat and has higher top speed but it hasn't happened yet (patrol 1's are faster than delivery vans so no problem).

I agree the chase rules are garbage. Fast, but garbage nonetheless. I've never found it terribly difficult to record vehicle positions and speeds in a chase and I think my players appreciate the accuracy.

I play vehicle acceleration very similar to how Eryk describes it. The first acceleration number is amount a vehicle can accelerate with a Free Action (no test). The second number is how much a vehicle can accelerate using a Simple Action (like a character Running) but this incurs a -2 penalty on all other actions. Finally, a character can make a Vehicle Test on which each hit adds 5 to the amount accelerated on top of the listed "running" acceleration rate.

I think the trick to understanding the rules is that acceleration is used when cars and people interact in combat while speed is used only when vehicles are acting in chase combat. Acceleration doesn't really have anything to do with chase combat and speed doesn't matter for vehicle to metahuman interaction. They're two separate attributes used in two separate ways.

Does that help?

I knew I should have included it

p. 161

"Engagement Range
Th ere are 3 Ranges of Engagement in Chase Combat: Close,
Short, and Long.
Close Range is very close—the vehicles are side by side or
otherwise in near proximity, and may attempt to ram each other
or cut each other off . Th is is close enough that a character could
attempt to jump from one vehicle to another. Th is is Short range
for most ranged weapon attacks.
Short Range is near to each other, but not close enough to
directly engage the other vehicle. Th is is Medium Range for most
ranged weapon attacks.
Long Range is within sight of the other vehicle, but trailing
a distance away. Th is is Long Range for most ranged weapon
attacks."

Compare to the weapon range tables, and you will see it comes very close.

THe base movement, the amount you can gain on net hits, if you look at the actual numbers you get out of doing the math, you'll see it comes close enough.