Here is the full list of all 23 Urban Trial Playground achievements.
Frontflip over the Hotdog in "Sup Dawg".
Unlock all Levels.
Score 250,000 points in one run on any Level.
Perform 5,000 total Tricks.
Score 100,000 points in one Combo.
Get x10 score multiplier.
Perform 1,000 Tricks playing as Tommy.
Perform 1,000 Tricks playing as Riley.
Crash 100 times.
Unlock Level 30.
Score 20,000 points by performing a single Wheelie.
Unlock Level 15.
Score 300,000 points in one Combo.
Score 500,000 points in one Combo.
Get x15 score multiplier.
Get x20 score multiplier.
Score 500,000 points in one run on any Level.
Score 20,000 points by performing a single Stoppie.
Unlock all Motorbikes.
Complete all Levels with 5 star rating.
Complete all Challenges.
Collect all Chips.
Complete "Late 2 Gate" with zero crashes and without hitting the brakes.