Abstract: Transport infrastructure investment increased substantially in Britain between the seventeenth and eighteenth century. This paper argues that the Glorious Revolution of 1688-89 contributed to transportation investment by reducing uncertainty about the security of improvement rights. It shows that road and river investment was low in the 1600s when several undertakers had their rights violated by major political changes or decrees from the King. It also shows that investment permanently increased after the Glorious Revolution when there was a lower likelihood that undertakers had their rights voided by acts. Together the evidence suggests that the political and institutional changes following Glorious Revolution made rights to improve infrastructure more secure and that promoters and investors responded to greater security by proposing and financing more projects.