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