Expansion of SR 18 from a two-lane rural road to a four-lane controlled-access freeway began in 1992 response to six fatalities in over 170 accidents in a ten-year period, giving the highway a reputation of being a "dangerous roadway". WSDOT widened SR 18 to four lanes and added new interchanges between SR 167 and the Green River within Auburn. The Washington State Legislature briefly planned to toll the new SR 18 freeway in January 1995 to pay off loans for re-construction, but the plan was protested by local residents and rejected months later in May. Additional work was completed in 1997 from the Green River to Southeast 304th Street in Covington, and in 2007 from Covington through Maple Valley and to Issaquah-Hobart Road. The western end of the freeway was extended in Federal Way through Peasley Canyon to I-5 in Federal Way, which was further improved in 2011 with the completion of interchange improvements to the "Federal Way Triangle".