For example when I use spike strips the car just drive 10 meters and stop and the suspect gives up. So i know that the pursuit is over when i use spike strips. Is there a way to make the suspects behavior more aggressive? I would like that there is a chance  that he trys to flee even with flat tires or that he is trying to shoot me or something else....

I don’t think you can change anything regarding what you stated but you certainly can enhance your pursuit experience by adding mods like Improved PursuitAI by @Echooo . That’ll at least add some immersion towards your backup units. 

 

2 hours ago, robin09g said:

Is there a way to make the suspects behavior more aggressive? I would like that there is a chance  that he trys to flee even with flat tires or that he is trying to shoot me or something else....

I mentioned this in an other post, but you can make it more difficult for yourself stopping a fleeing car by setting a rule for the event:
Only use stun-gun to shoot out purp-cars tires!
Stun-gun works fine for this, but only if you are very close to the purp-car, it greatly increases the difficulty and hence the gameplay.

Some times plugin-devs forget that LSPDfr is a game : ) and a game need to have some difficulties. Spike-mats are great in RL, because the task is to STOP the purp. In a game spike-mats are not so great, because they removes the chase-gameplay.
Game-development has a cardinal rule:
If you add a feature, there need to be a contra-feature, if you want balanced gameplay
I cant think of a contra-feature against spike-mats, other than solid tires : p
You also asks for higher frequency of random events in a chase.
There is one for traffic-stops, but non for chase end-games. It would be a good thing to add..
(It can be done In code -Should i make it?

 

In the LSPDFR pursuit menu (press N during a pursuit) you can choose to force lethal tactics which will result in backup units firing at the suspect. If they are armed, they will likely shoot back from their vehicle.