Transportation agencies must set reasonable times for completion of construction projects. Factors to be considered in determining contract time include materials, equipment, manpower, cost, and constraints such as weather, regulations, traffic, utilities, and user convenience. This report of the Transportation Research Board presents guidelines and recommendations for the establishment and enforcement of contract times. To develop this synthesis in a comprehensive manner and to ensure inclusion of significant knowledge, the Board analyzed available information assembled from numerous sources, including a large number of state highway and transportation departments. A topic panel of experts in the subject area was established to guide the researcher in organizing and evaluating the collected data, and to review the final synthesis report. The conclusions reached in this synthesis include the following: When establishing or modifying a time- estimation procedure, the performance of the procedure should be monitored, the effects of site conditions and terrain should be considered, and information should be obtained from state contractor associations. In determining contract time, a construction data file that covers the previous 3 to 5 yr should be used. The schedule should be reviewed and adjusted to reflect other factors, such as project size, availability of materials, and commitments of the agency engineering and inspection forces. Except for certain projects that must be completed within narrow time limits, there does not appear to be a need for highly restrictive contract duration times. The working- day and calendar-day methods have an advantage over the completion-date method in that the contractor is not liable for circumstances beyond his control; however, the agency must be careful to document each day that is charged. Suggested guidelines include: Agencies should be flexible in establishing contract time. Construction season time limits have merit for some work, particularly for paving and resurfacing projects. Once specified, contract time becomes a contractual condition and should be enforced. Time charges on working- day contracts should be administered uniformly and fairly. It appears desirable and equitable to prescribe liquidated damages for (a) the time that traffic and the public are inconvenienced and (b) supervision costs incurred by the agency. A formal, rational approach should be developed to determine contract time; it should be based on past experience and updated frequently.  The report for this topic can be purchased at https://www.trb.org/news/blurb_detail.asp?id=3478