Well, they were at least not allowed to congregate in large groups.
Public gatherings and the coming together of people in close quarters was seen as a potential agency for the transmission of the disease. The public health authorities believed that good ventilation and fresh air were "the best of all general measures for prevention, and this implies the avoidance of crowded meetings," (BMJ, 10/19/1918). This translated into the controversial and imperative measure of closing of many public institutions and banning of public gatherings during the time of an epidemic.
And those ill were isolated too:
The more restrictive methods of infection control issued by public health departments were quarantines and the isolation of the ill. These measures required a sacrifice of individual liberty for the societal good and therefore required a strong public health authority. Both the Illinois and New York State Health Departments ordered that patients must be quarantined until all clinical manifestations of the illness subsided. They held that the danger of the influenza epidemic was so grave that it was imperative to secure isolation for the patient (JAMA, 10/12/1918). The members of the APHA committee agreed in their report, saying that patients with influenza should to be kept in isolation. Because of the strain on facilities, only severe cases were to be hospitalized while mild influenza patients were to remain at home. The APHA also supported institutional quarantines to protect people from the outside world in establishments like asylums and colleges (JAMA, 12/21/1918). The use of institutional quarantines was applied to the many military training camps set up in the United States to prepare soldiers for war. These camps, with masses of men from throughout the country, were prime targets of huge influenza epidemics. The men were kept in strict isolation once ill and entire camps was often quarantined (JAMA, 4/12/1919). These measures were easily implemented in these camps where men were already committed to their country and the authority of the government.
There were some other restrictions, like sterilization, preventing the use of common utensils, and other germ theory measures, but severity varied by localities and municipalities. That's all I could find using a quick google search.
Street cars were thought to be a special menace to society with poor ventilation, crowding and uncleanliness. The committee encouraged the staggering of opening and closing hours in stores and factories to prevent overcrowding and for people to walk to work when possible (JAMA, 12/21/1918).
Okay, so there were some encouragement of not going/using streetcars
Most of these measures were sanitation and sterilization led by germ theory science, it seems transportation restrictions was pretty limited.