Information from many highway departments and agencies was assembled and analysed in this effort to record and evaluate current practices in the use of partial-lane pavement widening. Specific problems on partial-lane pavement widening projects (narrow work areas, acquisition of additional right-of-way, variable subgrade, reconditioning of existing pavement, reflective cracking, structure widening, surface and subsurface drainage, traffic during construction, access for abuting owners, and funding projects) have been addressed and practices have been developmed to meet specific needs. Nearly all partial-lane widening projects include provisions for placing an overlay over both the old and new pavement. In a few cases the overlay may be placed during the following construction season. The modification of the existing surface drainage, alignment improvement (by shifting the widening, where possible, to the inside of curves; replacement of small angles by a smooth curve), minimizing reflection cracks by provision of good subsurface drainage, compaction of widening trench at or near the optimum moisture content, provision of good shoulder support, and the use of substantial overlay to cover the joint) are some practices described. The open trench hazard, and advance coordination with abutting residents and businesses to avoid inconvenience are also discussed. Safety, capacity and maintenance are important factors in planning the widening projects. Long-range and short-range plans, project selection, citizen participation and factors which affect the decision-making process are outlined. The various aspects of design and construction are covered.  The report for this topic can be purchased at https://www.trb.org/news/blurb_detail.asp?id=3519