OK, just had to check something.... as I was saying, according to GE, it's 29.2 miles from Los Alamitos, AAF to LAX, with an approximate driving time of 37 mins.  Just two major freeways, but I would have thought that the San Diego Freeway was a more direct route.    go figure...
Reality check time:  All this assumes that the racers take a "commercial flight" out of LAX. (I don't recall any airport sightings)  Just wondering....  
 From the Los Alamitos area there are two routes, as noted, to LAX:
1.  405 North (straight shot)
2.  605 NOrth to the 105 West
You can access LAX from either the 405 or 105. 
Considering where they are and then time of day, I personally would take the 405 North.  I wouldn't even give the other route a thought.  I live near the 405/605 intersection and when I am planning to go LAX, route 2 never even crosses my mind.  (coming home however that's another story.   

 )  
Even if they did head in the direction of the 605, I would expect them to take the 605 south and then onto the 405 North.  
Traffic would be tough during that time period regardless however I would think the 405 would be a better bet.  
I'd say it would take them roughtly an hour give or take a few.  
Anyway, that's my 2 cents.