How does Chase Combat work? Options

[UmaroVI]

I'm really confused, and I'm hoping those of you who do understand how this works can clarify it.

SR4A 170 says that everyone makes a Vehicle test at the start of the turn with modifiers. Then, "The drivers with the most hits on either side are compared in an Opposed Vehicle Test."

Question 1: One of the modifiers is: "Then compare the Speed values of all vehicles on either side. Whichever side has the greater Speed value adds a +1 modifier for every 10 points (rounded down) that their Speed exceeds their opponents." Does this mean sum of all speeds on that side, highest speed, lowest speed, average of all speeds on that side, or what?

Question 2: the comparison (Opposed Vehicle Test). Is this a completely new test, rolled by the people who got the highest vehicle test on their side? Or do you use the results of the original vehicle test? If it is a new test, do the same modifiers apply?

Question 3: Under multiple vehicles, I am confused as to what is meant by the second paragraph. "Add the Speed values of all the vehicles on each "side" and compare totals. For every 20 points that the highest total Speed Rating exceeds the second highest total, apply an additional 01 dice pool modifier to all Chase Stunt Tests performed by the slower factions' vehicles." Does "slower factions' vehicles" mean all factions but the fastest, or all but the two fastest?

I also see some problems with this system not actually making any sense, but I might just be misunderstanding how the whole thing works, so I'll wait to discuss that.

[X-Kalibur]

How does Chase Combat work?

It doesn't.

[Hedrik]

I GMed one chase combat and it worked quite well.

Under some restrictions.
Reduce one of the 'sides' to just one vehicle. This way you can separate everything to independent chase combats.

Example:
3 Bikes chasing one car.
The first action in every turn is a pilot ground craft test with appropriate modifiers. (Here I suggest to take the lowest speed and give every other vehicle the bonus according to their speed difference /10)
Compare each roll of the bikes separate with the car.

This way it worked for me. It was fast enough to be fun and everybody had something to do.

There is just one thing left open in my scenario. How do people by-foot compare to slow cars, for example. A highly cybered sammy sould be able to follow a slow car or vespa or alike in a city.

[Hand-E-Food]

There is just one thing left open in my scenario. How do people by-foot compare to slow cars, for example. A highly cybered sammy sould be able to follow a slow car or vespa or alike in a city.

My math is: [km/h] * 0.8 = [m/round]; or [m/round] * 1.25 = [km/h]

A troll with 6 hits on sprinting can run at (25 + 2*6) * 1.25 = 46.25 km/h

That takes a simple action, so they can fire a shot in the same turn. However, I'm sure there's rules (and if not, make some) for how long one can sprint.

[Cheops]

As with all of SR4 your best bet is to ignore the rules as much as possible and just magical tea party it.

If you absolutely, positively must run it with rules I'd suggest you run it as an Extended Skill Test. Set the test interval to 1 minute and then decide on the Threshold -- I'd suggest 3 hits per chase vehicle (which can be extended by adding more vehicles) or a number of hits equal to the number of minutes it would take to drive the distance normally. Rigger makes 1 Extended test every round and then can use Chase Tactics with his other actions. Non-driver characters use their actions to increase the Rigger's drive test (eg. hacking grid guide to clear the way) or to hinder the opposition (eg. blow them up).

Let's the GM get a better narrative and avoids silly issues like grandma's on scooters maintaining pace with Eurocar Westwind's and the Picard Effect. Summon up Cain if you want a better understanding of the issues with the Chase system.