3.3 Routes, Parking & Driving Rules

Routes and Tunnel Restrictions

Where a HazMat load may travel is regulated by 49 CFR Part 397. A driver of a placarded vehicle must always operate over routes that minimize risk to populated areas, water supplies, and critical infrastructure.

• Designated routes. State and local authorities can designate preferred HazMat routes (often loops or bypasses around city centers). Where a designated route exists, drivers must use it even if it is longer.
• Prohibited routes. Many cities, tunnels, and bridges prohibit placarded vehicles entirely or limit them to certain hazard classes or hours. Watch for HazMat-prohibition signs.
• Avoid heavily populated areas, crowds, tunnels, narrow streets, and alleys unless there is no practical alternative or a designated route directs you there.
• A driver transporting Division 1.1, 1.2, or 1.3 explosives must carry a written route plan and follow it, and must also carry a copy of the federal regulations in 49 CFR Part 397.

The Railroad-Crossing Stop Rule

A vehicle that is required to be placarded for hazardous materials must stop at every railroad-highway grade crossing. Under 49 CFR 392.10, the driver must stop within 50 feet of, but not less than 15 feet from, the nearest rail — in other words, in the 15-to-50-foot zone — then check both directions for an approaching train before crossing.

The driver must not shift gears while crossing the tracks. A stop is not required when the crossing is:

• Controlled by a police officer or flagger, or
• Controlled by a functioning highway traffic signal showing green, or
• Officially marked as exempt or abandoned.

Parking Rules and Distances

Where a placarded vehicle may park is tightly controlled. Memorize these distances — the exam tests them directly.

The 5-Foot Rule

A placarded vehicle must be parked at least 5 feet from the traveled part of a public road. The only exception is a brief period needed for the necessities of operation — such as loading or unloading.

The 300-Foot Rule

A placarded vehicle must never be parked within 300 feet of an open fire. For loads of Division 1.1, 1.2, or 1.3 explosives, the 300-foot restriction also covers bridges, tunnels, buildings, and any place where people gather — the goal is to keep a potential blast away from people and critical structures.

Attendance When Parked

A placarded vehicle is "attended" only when a qualified person is awake, not in the sleeper berth, and within 25 feet of the vehicle with a clear view of it. That person must know the emergency procedures and be able to move the vehicle.

Safe-Haven Parking

A safe haven is a government-designated, approved, and supervised location where a vehicle carrying explosives may be parked unattended. Outside of a safe haven (or a secure carrier or consignee facility), a vehicle loaded with Division 1.1, 1.2, or 1.3 explosives must be attended at all times.

Think of the safe haven as the one planned, lawful place a driver can leave an explosives load — it is part of the route plan, not a roadside choice made on the spot.

Route Planning for HazMat

Good route planning is a driver responsibility, not just a dispatcher's job:

• Identify designated HazMat routes and any city, tunnel, or bridge prohibitions before departure.
• Plan fuel and rest stops that comply with the 5-foot and 300-foot parking rules and provide attendance where required.
• For explosives, pre-locate safe havens along the route and write the plan down.
• Avoid tunnels, congested areas, and crowds wherever a practical alternative exists.
• Carry the shipping papers within reach, the Emergency Response Guidebook (ERG), and — for Division 1.1/1.2 explosives — the written route plan and a copy of 49 CFR Part 397.

Driving Behavior

Once moving, the driver protects the load by driving smoothly: avoid sudden starts, stops, and sharp turns that can shift or rupture packages. Keep extra following distance, slow well before curves and ramps because of the high center of gravity, and never drive a vehicle with a known leak.