The Majority Of All Traffic Accidents Occur In The Urban Environment, Where There Is A More Complex Traffic Environment And A Higher Predominance Of Road Users That Are More Susceptible To Injury And Fatality In The Event Of An Accident. A Relatively Straightforward And Cost-effective Speed Management Measure, Involves Reducing Speed Limits. The Relationship Between Vehicle Speed, Accident Risk And Accident Outcome Severity Is Well Established In Traffic Safety Literature. Research Shows That Reduced Speed Is Likely To Bring About A Reduction In Average Travel Speed And Have A Positive Impact On Both The Number Of Accidents And Accident Outcome Severity. Other Secondary Benefits Are Also Derived Including: Reduced Fuel And Vehicle Operating Costs, And Significant Reductions In Vehicle Emissions And Noise. A Key Issue Surrounding The Effects Of Lowering Speed Limits In Urban And Metropolitan Areas Concerns The Impact On Mobility And The Environment. A Hypothesis That Is Investigated In This Literature Review Is That A Reduction In Average Travel Speed Brought About By Reducing Urban Speed Limits, Is Only Likely To Have A Marginal Impact On Travel Time. Research Tends To Support This Notion Given That Average Speeds Are Influenced By Many Other Factors Including Driver Attitudes And Preference; Roadway Design; Forms Of Traffic Regulation At Intersections; And Prevailing Traffic Conditions (levels Of Congestion; Weather; Etc).