The rules: OSHA, the MUTCD and the road authority

Before Tallgrass could close a lane of Larch Avenue for the first delivery, Owen Hartley had to answer three questions. Which workplace safety rules apply to people working near traffic? Which traffic control manual sets the standard for the signs, devices and layouts? And who owns the street and has to give permission? The answers come from three different places, and a contractor who knows only one of them will get something wrong.

Layer 1: workplace safety law

OSHA's construction standard on signs, signals and barricades, 29 CFR 1926 Subpart G (1926.200 to 1926.203) is short. Section 1926.200 requires signs and symbols where there are hazards, and 1926.200(g) says that traffic control signs and devices used to protect workers on or near highways must conform to Part 6 of the MUTCD. Section 1926.201 covers signaling: when signs, signals and barricades do not give enough protection, flaggers or other traffic controls must be used, signaling by flaggers must conform to the MUTCD, and flaggers must wear a red or orange warning garment, reflectorized at night. Section 1926.202 says barricades for protecting workers must also conform to Part 6 of the MUTCD, and 1926.203 gives definitions. By pointing to the MUTCD, OSHA turns the traffic manual into an enforceable workplace safety rule on construction sites.

OSHA's general construction rules also apply. Section 1926.21(b)(2) requires employers to instruct each employee in recognizing and avoiding unsafe conditions, which covers flagger training and training for anyone who works near traffic. Section 1926.601(b)(4) and 1926.602(a)(9) cover backup alarms and observers for trucks and earthmoving equipment, which matter for the internal traffic plan in lesson 12. The General Duty Clause, section 5(a)(1) of the OSH Act, can be used where a recognized traffic hazard is not covered by a specific rule. Texas has no state OSHA plan for private employers, so federal OSHA enforces these rules on Tallgrass's site.

Layer 2: the traffic control manual

Workplace safety law says what the employer must do; a traffic control manual says how. In the United States, the federal Manual on Uniform Traffic Control Devices (MUTCD) is the national standard for all traffic control devices on public roads, and Part 6 covers temporary traffic control. The current 11th edition was published in December 2023 and took effect in January 2024, and states had two years, until January 2026, to adopt it, either directly or through a state manual in substantial conformance. FHWA issued Revision 1 of the 11th edition, effective March 5, 2026, with minor technical and editorial corrections. Texas uses its own manual, the Texas Manual on Uniform Traffic Control Devices (TMUTCD). The 2025 TMUTCD took effect on January 18, 2026, and TxDOT has been revising it to stay in substantial conformance with Revision 1. On Larch Avenue, a city street in San Antonio, the TMUTCD applies along with the City's own right-of-way requirements, and for the sister job's driveway tie-in on a state highway posted at 65 mph, TxDOT's standard plans and specifications apply as well.

Traffic manuals use a deliberate vocabulary. A shall statement (a standard) is mandatory. A should statement (guidance) is the recommended practice unless engineering judgment or a study shows a good reason to do otherwise. A may statement (an option) is allowed but not required. Supervisors who write or review traffic control plans need to know which kind of statement they are relying on, because departing from guidance without a documented reason is hard to defend after a crash.

Layer 3: the road authority

The road authority owns the road and decides who may work on it. For Larch Avenue, that is the City of San Antonio, which issues a right-of-way permit, requires a traffic control plan for lane and sidewalk closures, may restrict closures to off-peak hours and can inspect the setup or revoke the permit. VIA, the transit agency, emergency services and nearby businesses have to be told when bus stops are moved or access changes. For a state highway posted at 65 mph, the road authority is the Texas Department of Transportation (TxDOT), which requires a permit for work in its right-of-way and sets its own layout and contractor requirements.

A permit is not a substitute for the safety rules, and the safety rules are not a substitute for a permit. On the Cottonwood Place job, the City's permit set the hours (closures only between 9:00 and 15:30 on weekdays, except under a separate night permit), the City approved the standard layout for the curb lane closure, and the workplace safety rules governed how Tallgrass and Mission Traffic Control LLC protected their workers inside that layout.

Traffic law and enforcement

Drivers are bound by traffic law, not by OSHA. The Texas Transportation Code requires drivers to obey flaggers and traffic control devices, and section 472.022 doubles the fine range for disobeying a warning sign or driving around a barricade in a construction or maintenance work zone when workers are present. The zone must be marked with signs showing where it begins and ends and stating that fines double when workers are present; mobile operations are excluded. Police enforcement and paid off-duty officers on major projects support the plan, but none of them replaces good layout and worker protection.

Who does what on Cottonwood Place

Owen wrote a short responsibility list for the traffic control on the project and put it in the site safety plan.

• The controlling contractor (Tallgrass Construction Inc.) coordinates all work near traffic on the site, gets the City permit, makes sure every subcontractor working near traffic follows the plan, and controls deliveries so trucks do not arrive before a closure is set up. Under OSHA's multi-employer citation policy, it can be cited as the controlling employer if it fails to use reasonable care to prevent or correct a hazard.
• Mission Traffic Control LLC prepares the traffic control plans for the City, supplies and maintains signs and devices, provides trained flaggers for the larger closures, and employs the traffic control supervisor who sets up, inspects and removes each closure.
• Each employer whose workers are exposed to traffic, such as Silva Earthworks and the concrete pumping subcontractor, is the exposing employer for its own workers and must protect them, even when it works inside Mission Traffic Control LLC's setup.
• Workers follow the plan, stay inside the protected area, report missing or damaged devices and refuse work that poses an imminent danger.
• The City approves the plan and permit and inspects.

A compliance check before the first closure

Owen built a small checklist program for each closure request. It checks that the three layers are covered before a closure goes on the schedule.

# Pre-closure compliance check (invented data for one closure request).
request = {
    "permit number on file": True,
    "permit hours cover the work": True,
    "traffic control plan approved by road authority": True,
    "plan uses current manual layouts": True,
    "flaggers trained, proof of training on site": True,
    "high-visibility apparel to required class": True,
    "advance warning signs and taper in plan": True,
    "pedestrian route in plan": False,
    "deliveries held until setup confirmed": True,
}
missing = [k for k, ok in request.items() if not ok]
print(f"{len(request) - len(missing)} of {len(request)} items in place")
for k in missing:
    print("  missing:", k)
print("Closure may go on the schedule:", "yes" if not missing else "no")

8 of 9 items in place
  missing: pedestrian route in plan
Closure may go on the schedule: no

On the first run, the pedestrian route was missing: the standard layout closed the curb lane but said nothing about the sidewalk beside the gate, where people waited for the bus. Mission Traffic Control LLC added a protected sidewalk route and moved the bus stop marker with the transit agency's agreement before the closure was approved.

When the rules disagree

Sometimes the layers seem to pull in different directions. The road authority's permit may allow a closure only from 9:00 to 15:30, while the concrete supplier wants to start the pour at 6:00. The manual's layout may call for a taper longer than the block allows. A subcontractor's own safety program may require a barrier where the City's standard drawing shows only cones. Owen's rule on the Cottonwood Place job was simple: follow the most protective requirement, and where two requirements genuinely cannot both be met, stop and resolve it with the people who wrote them before the work starts.

In practice that meant three conversations. The pour start was moved to fit the permit, or a separate early-start permit was requested from the City with a plan to match. The taper problem was solved by moving the advance warning signs and the start of the taper to the approach block, which the City approved. And where a subcontractor's program asked for more protection than the standard drawing, Tallgrass provided it, because nothing in the permit or the manual forbids a contractor from protecting workers better than the minimum.

Keeping records

Records show that the rules were followed, and they matter when something goes wrong. For every closure, Tallgrass kept the permit, the approved traffic control plan and any revisions, the flaggers' training cards and the record of each flagger's site checkout, the inspection sheets filled in by the traffic control supervisor at set-up and during the shift, and notes of any incidents, near misses or complaints. An OSHA compliance officer, the City's inspector or a lawyer after a crash will ask for exactly these documents.

Good records also help the next job. When a closure works well, its plan and inspection notes become the starting point for the next similar closure. When something goes wrong, the records show what was in place and what needs to change, so the same mistake is not repeated on the next block or the next project.

Questions to ask before any work near traffic

Before any crew works near traffic on the job, the foreman can answer five questions in a minute. Who owns this road, and do we have their permit for today and this time? Which plan covers this work, and is it the current revision? Which layout in the manual does it follow, and has anything on site changed since it was drawn? Who is the traffic control supervisor, and how do I reach them? Are the people directing traffic trained, equipped and carrying proof? If the foreman cannot answer one of these, the work waits until they can.