Why do traffic diversion bids come in low in Qardho?

A low traffic diversion bid in Qardho usually means the bidder priced the signed route and left out what keeps it working: signs, night cover, drainage, access to premises, and reinstatement. Traffic diversions underbidding risks in Qardho sit in those missing lines, not in the asphalt quantity. Read the bill of quantities against the diversion drawing before you compare totals.

What gets left out of a traffic diversion bid?

What disappears first is everything that leaves no visible mark on the road. A priced diversion line may cover gravel, grading and a culvert, while the items that keep traffic moving during the works sit outside it.

Common omissions in diversion pricing include:

• Signs, cones, barrels and reflective markings, plus someone to reset them after wind or traffic knocks them over.
• Security and lighting at night, and flaggers at the tie-in points where diverted traffic rejoins the existing road.
• Side drainage and culverts under the diversion, so the running surface survives the Gu and Deyr rains.
• Access to shops, homes and mosques along the closed section.
• Reinstatement of the diversion ground, plus dust control while it is in use.

Ask each bidder to list the diversion items they have priced and the ones they have excluded. An omission is easier to find in that list than in a total. Confirm the required sign layout and any permit conditions with the municipal engineer's office before comparing bids.

How do weak cost assumptions show up in the numbers?

Weak assumptions show up as thin allowances for the work that depends on time, weather and people, not as a low rate on one line. A bidder who assumes the diversion stays open for the stated programme, with no reseeding after each rain, has priced a site that may not exist.

Check these allowances against the method statement:

• How long the diversion is assumed to stay in place, and whether reshaping or re-gravelling is priced more than once.
• Water for compaction and dust control, and where it comes from.
• Whether the bidder carries the cost of moving the diversion as the works advance.
• Whether supervision, security and sign maintenance are inside the bid or assumed to be someone else's job.

A rate is only comparable when the assumption behind it is written down. Ask for the assumptions in writing, then compare them between bidders. Do not treat a low total as a saving until the exclusions are known. Check what the contract allows on remeasurement before award, and never rely on a verbal promise to add items later.

How does this create conflicts near work zones?

Conflicts near work zones grow when the diversion is under-resourced, because the gap is filled by improvisation on the day. A missing flagger at a tie-in, a culvert that ponds, or a closed shop entrance turns a technical problem into a dispute.

Where the priced scope is thin, expect pressure at:

• Tie-in points, where diverted traffic meets the working edge and speeds change.
• Shop and gate entrances, where a contractor may close access to save time.
• Drainage crossings, where water held by the diversion backs up onto adjoining ground.

A supervisor can catch this early by walking the diversion line with the traffic management plan and the bill of quantities in hand, and recording what is not built. Ask the municipal engineer's office which office handles complaints on the route, so the client has a place to send them. Keep instructions in writing so any added work is measured, not argued about later.

What to do next

Take the diversion drawing and the bill of quantities to the proposed route before award. Walk the line, mark every item the bid does not cover, and send one written clarification listing those items to each bidder. Ask for the priced traffic management plan and the maintenance allowance in the same reply. Compare bids again only after those answers arrive.