Street design guides play a central role in the evolution of transportation systems in society. They are instruction manuals for engineers and planners to build new streets and repair or replace older streets. In theory street design guidance is based solely upon sound engineering judgment backed up by evidence based research to ensure streets ensure the health, welfare, and safety of the public. In practice street design guides are a reflection of a society’s culture and values. As they are developed, they are subject to the influence of advocacy and the personal biases and opinions of the people participating in the process. To reduce car dependency and achieve Vision Zero goals, it is necessary to understand how historical cultural values impact present day design guidelines. This discussion will point out the legacy values that are ingrained in guidance, discuss key research that impacted guidance, and highlight critical areas that require research attention.