An interim speed limit for a new or reconstructed highway shall be determined and posted before the highway is opened to traffic.

To set an interim speed limit, a traffic and engineering investigation will be conducted.

The traffic and engineering investigation will include a review of:

To set an interim speed limit at a speed that is less than the prima facie speed applicable to the highway, a commission minute order or a city ordinance setting the interim speed limit is required.

Warning signs and advisory speed signs may be used on a highway with an interim speed limit to alert drivers to any hazards.

When traffic speeds have stabilized on a highway, an 85th percentile speed study will be conducted as discussed under Section 2 of this chapter. The interim speed limit will be used on the highway until the maximum speed for the highway is determined following the conclusion of that investigation.