Credit to HappyThumbsGaming for their excellent descriptive guide:
There are a total of 39 Red Bricks to collect throughout the game. Unlike most other LEGO games all of the red bricks in this one are free and do not require any studs to purchase. The breakdown is as follows:
– 3 are unlocked automatically at the beginning of the game
– 15 are found in either Story or Free Play mode of the Special Assignments
– 21 are found in the world (1 in each district/area except Lady Liberty Island)
The locations of each of the Red Bricks are as follows:
1) Ring Tone Honk – Automatically Unlocked
2) Ring Tone Donkey – Automatically Unlocked
3) Ring Tone Belch – Automatically Unlocked
4) Fast Build – Special Assignment #1
5) X2 Studs- Special Assignment #2
6) Unlimited Dynamite – Special Assignment #3
7) Super Throw – Special Assignment #4
8) X4 Studs – Special Assignment #5
9) Super Astro Crate – Special Assignment #6
10) Super Safe Crack – Special Assignment #7
11) Super Break and Enter – Special Assignment #8
12) Costumes – Special Assignment #9
13) Attract Studs – Special Assignment #10
14) Extra Hearts – Special Assignment #11
15) X6 Studs – Special Assignment #12
16) X8 Studs – Special Assignment #13
17) Attract Bricks – Special Assignment #14
18) X10 Studs – Special Assignment #15
19) Data Scan Upgrade City Challenges – Cherry Tree Hills
20) Data Scan Upgrade Character Challenges – Auburn
21) Data Scan Upgrade Red Bricks – Auburn Bay Bridge
22) Data Scan Upgrade Tokens – Fort Meadows
23) Data Scan Upgrades Clues – Bluebell National Park
24) Nitrous For All – Blackwell Bridge
25) Super Color Gun – Uptown
26) Super Fast Travel – LEGO City Airport
27) Ring Tone Gas – Paradise Sands
28) Fall Rescue – Fresco
29) Invincibility – King’s Court
30) Wonder Whistle – Downtown
31) Larger Vehicle Boost – Festival Square
32) Super Axe Smash – Pagoda
33) Instant Vehicles – Bright Lights Plaza
34) Super Ram – Crescent Park
35) Collect Sat Nav Studs – Heritage Bridge
36) Ring Tone Pig – Grand Canal
37) Super Drill Ride – Crosstown Tunnel
38) Police Siren Hat – Albatross Island
39) Super Ray Gun – Apollo Island
Also, here is a video walkthrough of the red brick locations:
Credit to packattack04082.