According　to　the　Chinese　Design　Specification　for　Highway　Alignment　(JTG　D20-2006),　eight-lane　expressways　should　be　paved　with　an　inside　shoulder　of　2.5m;　however,　this　regulation　is　rarely　obeyed　in　engineering　practice.　On　the　basis　of　driving　simulator　experiment,　this　research　examined　the　impacts　of　inside　shoulder　on　vehicle　operation　with　and　without　the　speed　limitation.　A　virtual　scenario,　consisting　of　five　expressways　with　different　inside　shoulder　widths,　was　created　and　displayed　in　driving　simulator,　and　vehicle　operational　data-speed　and　lane　position-were　recorded.　Authors　used　analysis　of　variance　(ANOVA)　and　contrast　analysis　to　examine　whether　inside　shoulder　width　had　statistically　significant　effects　on　travel　speed　and　lane　position.　Analytical　results　indicated　that　there　is　a　kind　of　quadratic　relationship　between　inside　shoulder　width　and　driver＇s　speed　choice,　while　driver＇s　speed　choice　is　not　significantly　affected　by　inside　shoulder　width.　What　is　more,　inside　shoulder　width　has　statistically　significant　effects　on　vehicle＇s　lane　positions,　and　vehicle＇s　lane　position　is　negatively　correlated　to　inside　shoulder　width.　Specifically,　the　vehicle　can　be　maintained　at　the　center　of　lane　when　the　inside　shoulder　width　is　2.5　m.