Pennsylvania Bridge Law: 41-Foot Kingpin Rule and Axle Limits
Pennsylvania caps combinations at 80,000 lb, holds tandems to 34,000, and allows a 53-foot trailer only when the kingpin-to-rear-axle-group distance is 41 feet or less. Its single-axle rules are more detailed than most states', and enforcement on I-78, I-80, I-81, and the Turnpike is aggressive.
By Avery Schwartz · Former CDL-A driver, 3 years OTR · Updated 2026-09-15
The numbers at a glance
| Limit | PA | Where it comes from |
|---|---|---|
| Gross weight | 80,000 lb | 75 Pa.C.S. 4941 |
| Single axle | 20,000 lb steer; 22,400 lb non-steer axle spaced 8+ ft from neighbors | 75 Pa.C.S. 4943; federal 20,000 controls on the Interstate |
| Tandem axle | 34,000 lb | 75 Pa.C.S. 4943 |
| KPRA / wheelbase | 41 ft, kingpin to centerline of rear axle or axle group | PennDOT size & weight page; 53-ft trailer |
| Bridge formula applies? | Yes | Federal formula on the Interstate; industry references report it on all routes — verify with PennDOT |
Legal limits change and enforcement varies by road. Confirm anything you're betting a ticket on with PennDOT / PSP.
How Pennsylvania applies the bridge law
Pennsylvania's gross limit is 80,000 lb for any vehicle or combination (75 Pa.C.S. 4941). The axle section, 4943, is more granular than most: the steering axle is capped at 20,000, non-steering single axles are allowed 18,000 when less than 6 feet from a neighbor, 22,400 when 6 to 8 feet apart or more, and two consecutive pairs of axles — your tandems — may carry 34,000 lb each. On the Interstate, federal law still holds a single axle to 20,000, so plan on that number for the steer and drives.
Trailer geometry follows the eastern standard. PennDOT's size and weight page states that a single trailer may be up to 53 feet long provided the distance between the kingpin and the centerline of the rear axle or axle group does not exceed 41 feet. Measured to the center of the tandem, a 53-foot van has some room but not unlimited room; tandems slid to the very back of a long rail can exceed 41.
Pennsylvania has a deserved reputation for enforcement. State Police and PennDOT operate fixed and portable scales on the I-78, I-80, I-81, and I-95 corridors and on the Turnpike, and Pennsylvania's overweight fine schedule escalates quickly with pounds over. The state also posts many secondary bridges below legal weight; those postings are enforced.
How to slide your tandems for Pennsylvania
Keep the kingpin-to-tandem-center distance at 41 feet or less, then slide for weight. Pennsylvania also has hills that move fuel around the tanks, so leave a little margin on the drives if you scale with quarter tanks and fill at the Flying J before the Turnpike.
Worked example. You scale at the first CAT after the shipper: steer 11,800, drives 35,300, trailer tandems 31,900, gross 79,000. Gross is legal; the drives are 1,300 over. Sliding the tandems forward (toward the cab) moves weight from the drives to the trailer axles. On a trailer with 4-inch hole spacing, a hole is worth roughly 250 lb, so 1,300 lb needs six holes: drives about 33,800, tandems about 33,400. Both groups are under 34,000 with a few hundred pounds of margin, and the gross hasn't changed. Now check the geometry for Pennsylvania using the row in the table above — and if you'll cross into a stricter state, set for that one instead. The Tandem Slide Calculator does the hole math for your trailer's actual rail spacing and tells you which direction to move.
Common tickets in Pennsylvania
Based on the statutes above and what drivers commonly report; citation practice varies by officer and county, so treat this as a watch list, not a fine schedule.
- Tandem over 34,000 or gross over 80,000 — the most common citations; PA fines are per-pound over and can run well into four figures on a big overload.
- KPRA over 41 feet on a 53-foot trailer, typically written along with an overlength charge.
- Posted-bridge violation — crossing a bridge posted below your weight, common on state routes and local roads.
Pennsylvania bridge law FAQ
What is Pennsylvania's kingpin-to-rear-axle limit?
41 feet from the kingpin to the centerline of the rear axle or rear axle group on a 53-foot trailer, per PennDOT's size and weight limitations page.
Why does Pennsylvania list 22,400 on a single axle?
75 Pa.C.S. 4943 allows 22,400 lb on a non-steering single axle spaced far enough from adjacent axles. The steer axle is limited to 20,000, and federal law caps any single axle at 20,000 on the Interstate.
Does Pennsylvania use the federal bridge formula?
Federal formula limits apply on the Interstate. Industry references report Pennsylvania applies it on all routes; the state statute uses its own axle-spacing rules in 4943. Verify with PennDOT for non-Interstate details.
Is there a weight tolerance in Pennsylvania?
No tolerance appears in 4941 or 4943. Plan on the raw numbers.
Related
Sources
- PennDOT — Size and Weight Limitations (53 ft / 41 ft kingpin)
- 75 Pa.C.S. 4943 — Maximum axle weight of vehicles
- 75 Pa.C.S. 4941 — Maximum gross weight of vehicles
- J.J. Keller — U.S. KPRA allowances (Pennsylvania 41 ft)
This page is a driver's summary, not legal advice. Statutes are quoted or paraphrased from the sources listed; where we couldn't verify a figure from an official source we've said so.