Reliability of travel time is increasingly becoming an important part of transport policies around the world. However, a recent review of policies in OECD countries shows that despite its importance, only few countries monitor reliability or explicitly incorporate reliability into transport policy making. The role of the government may be crucial in delivering optimal levels of reliability. A number of policy options are available to improve reliability. Active management of the network through ramp metering is recognized as an efficient way to control motorway traffic and field tests of ramp control strategies show benefits on average travel time. Far less is said on reliability benefits of ramp metering. There are only few studies that specifically monitor improvements in travel time variability. In this paper we present findings on a case study of applying ramp metering on a French motorway A6W near Paris. We apply a number of indicators for travel time variability before and after introducing ramp metering. In order to take into account reliability in policy impact evaluation, cost-benefit assessment provides consistent framework to assess the monetised benefits. We therefore also calculate monetary value of reliability benefits of ramp metering and finally discuss policy implications of our results. We suggest that failing to unbundle time saving benefits of a project between average travel time and the variability in travel time is likely to lead to sub-optimal policy solutions. We also argue that managing existing capacity better can be a cost-effective way to improve both average travel time and the variability in travel time.