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Title 23

Displaying title 23, up to date as of 6/10/2026. Title 23 was last amended 6/10/2026.
There have been changes in the last two weeks to Subchapter G.
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Title 23HighwaysPart / Section
Chapter IFederal Highway Administration, Department of Transportation1 – 999
Subchapter GEngineering and Traffic Operations620 – 680
Part 620Engineering620.101 – 620.203
Part 624Interstate System Access624.1 – 624.13
Part 625Design Standards for Highways625.1 – 625.4
Part 626Pavement Policy626.1 – 626.3
Part 627Value Engineering627.1 – 627.9
Part 630Preconstruction Procedures630.102 – 630.1112
Part 633 [Reserved]
Part 635Construction and Maintenance635.101 – 635.606
Part 636Design-Build Contracting636.101 – 636.514
Part 637Construction Inspection and Approval637.201 – 637.209
Part 645Utilities645.101 – 645.309
Part 646Railroads646.101 – 646.220
Part 650Bridges, Structures, and Hydraulics650.101 – 650.809
Part 652 [Reserved]
Part 655Traffic Operations655.601 – 655.607
Part 656Carpool and Vanpool Projects656.1 – 656.7
Part 657Certification of Size and Weight Enforcement657.1 – 657.21
Part 658Truck Size and Weight, Route Designations—Length, Width and Weight Limitations658.1 – 658.23
Part 660Special Programs (Direct Federal)660.501 – 660.519
Part 661Tribal Transportation Facility Bridge Program (TTFBP)661.1 – 661.57
Part 667Periodic Evaluation of Facilities Repeatedly Requiring Repair and Reconstruction Due to Emergency Events667.1 – 667.9
Part 668Emergency Relief Program668.101 – 668.215
Part 669Enforcement of Heavy Vehicle Use Tax669.1 – 669.21
Part 680National Electric Vehicle Infrastructure Standards and Requirements680.100 – 680.118