Tracking missiles comprise a system of yellow eco racing weapons featured in Jak X: Combat Racing, including homing missiles and their dark eco upgrade strike missiles. This weapon will fire a volley of missiles (two for the former and four for the latter) that seek out targets previously locked on to as indicated by a red reticle (or green for drone targets).
The missiles themselves are silver in color with red trim, leaving behind yellow or purple streaks depending on the variation. Acquisition of this weapon is indicated by missile icons, the homing missiles having two missiles and the strike missiles having four.
This weapon is highly valuable for its tracking capabilities, as the only times the weapon misses is if the missiles collide with a structure on the track or if they are fired without locking on to a target (which can sometimes happen when the player incorrectly anticipates the weapon locking on due to the target being too close in proximity). Aside from their homing capability, tracking missiles also pack immense power and a hit from both volleys will take down all except the heaviest armored cars.
Strike missiles on the other hand can do the same, but require only one volley to do so, two meaning certain death. This is balanced by the ease of which tracking missiles are deflected, as any red eco rear weapon pick-ups will be sufficient in deflecting them once, even though this still leaves a second potentially lethal volley.
Tracking missiles are thus dangerous enough that you should always try to keep a rear weapon loaded. This makes these substantially less dangerous against human opponents, though the second volley still allows for a potential hit if you do not manage to reach another red pick-up in time.