A stroad is a thoroughfare that combines the features of streets and roads. Common in the United States and Canada, stroads are wide arterials that also provide access to strip malls, drive-throughs, and other automobile-oriented businesses.
Stroads have been criticized by urban planners for safety issues and for inefficiencies. While streets serve as a destination and provide access to shops and residences at safe traffic speeds, and roads serve as a high-speed connection that can efficiently move traffic at high volume, stroads attempt to serve both purposes. Critics argue they are often an expensive, inefficient, and dangerous compromise.
In 2011, the American civil engineer and urban planner Charles Marohn, founder of Strong Towns, coined the word "stroad" as a blend of the words street and road to illustrate what he characterized as failures in the North American pattern of development. The concept of the stroad was popularized in large part as a result of an April 2021 short documentary by the Canadian-born, Amsterdam-based Jason Slaughter of the urban planning YouTube channel Not Just Bikes.
According to Charles Marohn, a stroad is a combination of two types of vehicular pathways: streets and roads. Mahron describes a street as "complex environment where life in the city happens". Streets are lined with buildings, such as houses, stores, and offices, whose entrances and exits open onto the street. As such, streets must accommodate both cars and pedestrians, through-traffic and entrances/exits from adjacent buildings, and temporary parking and delivery vehicles. As this complexity greatly increases the risk of accidents, an ideal street will have low speed limits, enforced by traffic calming features such as narrow lanes.
Conversely, Mahron describes roads as a "high-speed connection between two places". To mitigate traffic and reduce the risk of accidents, an ideal road will have limited entrances and exits, no parking, and strict segregation of vehicular and pedestrian traffic. They also have wide lanes, and are designed to run as straight as possible, only making gentle curves where necessary.
As stroads attempt to function as both a street and road, they will often combine features of both. Like a street, stroads are lined with buildings whose entrances and exits open directly onto the stroad. However, like a road, stroads permit vehicles to travel at high speeds, and will have wide lanes and be generally straight to accommodate them. In essence Marohn defines a stroad as a high-speed road with many turnoffs, and lacking in safety features.
Stroads began to emerge in the United States and Canada in the aftermath of World War II, as car ownership became widespread and suburbanization accelerated.
Some stroads were created when streets were expanded or widened, often with the aim of improving mobility. This was often done without proper access management implementation, and under the influence of engineering codes that emphasized speed and traffic flow rather than safety, resulting in the street becoming a stroad. Other stroads were created when developers began adding private accessways onto roads. As the number of accessways increased, so did congestion and collisions on the road, requiring traffic control additions such as traffic signals.
Dutch urban planner Willem Zurborg argues that this conversion of streets and roads into stroads was a consequence of local governments designing their roadways to fulfill the functions of flow roads, distributor roads, and access roads (ie, streets) simultaneously. Dover and Massengale make a similar argument, noting that the general public is often not aware of the functional distinction that engineers make between streets and roads. In the English-speaking world, street names often end with 'road' and vice versa due to historical reasons; this may be misleading and not align with the current de facto traffic situation.
By combining the high speeds of roads with the complexity of streets, stroads put both pedestrians and drivers at elevated risk. A 2021 report by the Governors Highway Safety Association found that 60.4% of pedestrian fatalities from motor vehicles in the United States occurred on stroads.
The design of stroads encourages motorists to drive at dangerously fast speeds. Vision Zero Coalition's 2018 report explains that the wide lanes and lack of sharp turns in stroad design give drivers a false sense of safety, which subconsciously encourages them to drive at dangerously fast speeds. Stroads in the United States and Canada typically have legal speed limits between . But since the design speed is much higher, motorists frequently drive at up to . Therefore, simply reducing the posted speed limit (PSL) with a traffic sign, a widely adopted strategy, will not work. "If the road [design] ... suggest[s] that the PSL is too low, drivers may simply ignore it".
This is a problem because the frequent entries and exits onto stroads create many points of conflict and potential collisions for drivers to navigate. Driving at high speeds reduces the length of time drivers have to react to these hazards, increasing the risk of an accident. It also means any collision will have a much higher kinetic energy, increasing their severity.
The quality of sidewalks next to stroads is often poor. Many stroads do not feature any sidewalks at all. In the case of stroad-like suburban residential streets, sidewalks are sometimes deliberately left out by design in order "to further the rural image". Sometimes there are only "painted sidewalks" next to a strip mall, without curbs or traffic bollards to protect pedestrians against vehicles that may deviate from the road. Stroads also often lack other pedestrian safety features, such as crosswalks and adequate street lights.
At intersecting stroads, vehicles often need to decelerate from a high to a low speed to make a sharp turn right from a long turn lane parallel to the sidewalk; this makes walking there particularly dangerous for pedestrians. Sidewalks are sometimes too narrow, feature many obstructions such as street lights, as well as driveway cuts, which make them pedestrian-unfriendly. These obstacles may force pedstrians off the sidewalk and onto the edge of the stroad, putting them at further risk.
Marohn argues that "a person on a sidewalk has no defense at all if a vehicle leaves the roadway at stroad speeds". He points out that traffic lights, such as those next to the State Street stroad in Springfield, Massachusetts, are often designed with shear pins at the base so as to break off if a vehicle happens to crash into it. Although this design increases the safety of the driver and any passengers, it also significantly decreases the safety of any pedestrians who may be standing or walking on the sidewalk behind the traffic signal. Marohn was astonished to discover that a bench had placed right next to this breakaway traffic light pole, "inviting people to sit in a place where the chance of a driver losing control and going off the roadway at high speeds is so great that the city installed breakaway poles."
Stroads are often billed as a way to make traveling by car more efficient; however, this is not always the case. Despite the high speeds that stroads were designed for, in practice they frequently end up being clogged with cars seeking access from the many entrances. As a result, the average speeds on stroads are low due to traffic congestion. Widening stroads to counter congestion usually only leads to induced demand and extra costs.
In his commentary, Marohn states that stroads do not function well as either a street or a road. By trying to be "all things to all people", stroads end up failing at the functions of both.
Dover and Massengale (2014) state that the design of roads were originally modeled on the railroad, as they were intended to serve the same function: namely, providing an efficient connection between two populated places, such as cities, towns, or villages. Streets, on the other hand, formed networks within a single place to facilitate travel within its boundaries. They argue two systems functioned well as long they were kept separated, resulting in increased financial productivity in the region they served. However, they warn that "we reconfigure our streets to have the characteristics of roadsâÂÂas stroadsâÂÂwe are no longer able to capture the value of shar[ing] the space."
Jason Slaughter, of the urban planning YouTube channel Not Just Bikes, points out that when the Netherlands implemented clear functional distinctions between motorways (highways), roads, and streets in the 1990s. it led to increased safety, traffic flow, and cost-effectiveness, while also having the effect of reducing car dependency and increasing walkability, cyclability, and general livability. The change resulted in a 30% decrease in expected traffic deaths between 1998 and 2007. Slaughter points to this difference in outcomes to argue that North American stroads are "inefficient", as well as ugly, dangerous, and more expensive.
Marohn (2017) stated that stroads "are enormously expensive to build and, ultimately, financially unproductive". This is because "stroads are built to a highway standard, their lanes are very wide, and there are never [fewer] than four lanes", or "at least three through lanes", and they usually take up extra space for shoulders and clear zones. Stroads feature many more entrances and exits than limited-access highways and roads and thus require more turning lanes, and because stroad vehicle speeds may be higher than on a street, the turning lanes are much longer to allow vehicles to decelerate and reduce the risk of rear-end collisions; this means stroads require more and longer turning lanes, which are more expensive to build and maintain and take up more space than streets and roads do. The high frequency of accesses to a stroad with much traffic often prompts the construction of traffic lights at intersections, which may cost up to $250,000 to build (excluding maintenance costs).
An extreme example of this is found on the intersection of Charleston Boulevard with Decatur Boulevard in Las Vegas, which features seven approach lanes, each of which has traffic lights. The larger size of stroads compared to streets and roads means they require more space which needs to be purchased, flattened, and asphalted, which reduces the property value of the land, increases the cost of flood protection infrastructure, and adds regular asphalt and traffic control system maintenance costs. Compared to households along urban streets, stroads tend to double the costs that households pay on the construction and maintenance of infrastructure, as well as the delivery of public services, while the tax revenues per acre of properties along stroads are lower compared to urban commercial streets.
The space taken up by stroads, as well as the large areas dedicated to parking lots at the destinations of cars using stroads, result in low-density land use (typical for urban sprawl). This makes stroad environments financially significantly less productive and tax-generating than a street, but with significantly more infrastructure and thus high-cost per area maintenance costs, so that they become a net-negative and financial burden for cities, and they cannot therefore sustain themselves.
Stroads are frequently characterized by their detractors as ugly, giving rise to built environments that are unpleasant to spend time in. The stroad can be found where urban sprawl and car-centric development patterns are used: it 'seems confused', and is characterized by 'no sidewalk, no shade, and a lot of parking'. Whereas stroads often feature a repetitive pattern of retail franchises on the side with very few sidewalks for pedestrians, there are usually large parking spaces for drivers. In Lexington, Kentucky, where such situations are commonly found in modern suburban commercial areas, a survey of elderly residents found that respondents instead desired 'protection from traffic, reduced noise, seating and shade, dedicated sidewalks, and increased building frontage.'
Stroads' lack of safety features makes it dangerous to travel along or across them by foot, bicycle, or other alternative forms of transportation. As such, if an area is dominated by stroads, residents will feel pressured to travel by car whenever possible. This is known as car dependency, and has numerous drawbacks, including increased pollution and higher infrastructure costs for local governments.
Walking for a distance of along a stroad (Farm to Market Road 1960 or Cypress Creek Parkway) in Houston motivated Jason Slaughter of Not Just Bikes to reflect upon and criticize the design of the roadway, and explore how urban planning could be done in a more safe and efficient manner (for example, by improving walkability and reducing car dependency). The rather narrow sidewalks, and in the middle section (crossing a bridge and a railroad) no sidewalk at all, were right next to fast-driving vehicular traffic ( , creating an extremely unsafe and unpleasant environment for pedestrians. Yet, the fact that the grass where one would expect a sidewalk was well-trodden, as well as Google Street View images which also appeared to show regular use, was evidence to Slaughter that a significant number of pedestrians apparently saw or had no other option (such as taking a car, taxi or bus) than to walk along this dangerous stroad to get to their destinations without basic pedestrian protections. He argued: "There is no excuse for this. If you have enough room for 7 lanes of car traffic, then you have enough room for a sidewalk. Or a bicycle path."
Arguing that stroads represent a poor return on investment and a safety hazard, Charles Marohn suggested that stroads should either be converted to a street, for land access, or a road, for mobility. Conversion to a street would involve slowing traffic, prioritizing people over cars, and encouraging complex community interactions and solutions. Conversion to a road would involve separating the road from shops and reducing the number of access roads.
To help people comply with the legal speed limit, traffic engineers need to design roads, and streets so that they are self-explanatory. This is called traffic calming. Roads and streets that implement traffic calming measures may use physical and perceptual cues to subconsciously trigger drivers to drive slower and more cautiously due to perceived danger. Examples include "narrower lanes, tighter corner radii, gateway treatments, changed roadway surface materials and appearance, mini roundabouts and other speed management techniques" such as speed bumps.
According to Charles Marohn, the famous Champs-ÃÂlysées in Paris was effectively a stroad as recently as 2001. In the middle of the avenue were three automobile traffic lanes in either direction, ostensibly fulfilling the function of a road. A wide buffer of trees existed on either side of the road area, separating the roadway from slip lanes for slow-driving traffic. These slip lanes fulfilled the function of streets, providing access to parking, sidewalks, shops and restaurants. Because the street and road areas of the Champs-ÃÂlysées were physically separated, this stroad environment actually managed some success in allowing both safe high-speed traffic (up to ) in the center roadway and a productive street environment on the sides. however, the slip lanes are fully pedestrianized, while the center roadway functions as a true road.
The Esplanade in Chico, California is, according to Marohn, a rare example of a successful 'stroad' akin to the 2001 version of the Parisian Champs-ÃÂlysées in that buffers of trees physically separate the high-speed 'road' part in the middle from the two low-speed productive 'streets' on the sides (lined by houses which had high property values). He contrasted the Esplanade to Mangrove Avenue, a stroad just five blocks to the east in Chico that runs parallel to the Esplanade, but which he claims has the typical issues of a stroad, in that the street and road functions are not physically separated, and the environment is low-density and much less productive, with gas stations, strip malls and other car-oriented businesses.
Unlike Marohn, however, Jason Slaughter of Not Just Bikes does not categorize such traffic situations as a "stroad", but as "a road with streets on either side to access houses". Taking the Nieuwe Dedemsvaartweg (Provincial road N377) outside Nieuwleusen and the (s108) in Amstelveen in the Netherlands as examples, he used the fact that access from the middle to the sides is very restricted (through a limited number of roundabouts) to argue that they are three separate ways: the middle is a road, the sides are streets; there is no "stroad".
In recent years, traffic engineers in North America cities such as Boston, Houston, and St. Louis, are reshaping their fundamental street design and reworking traffic laws so that safety is prioritized. , the city of Boston is studying how to minimize pedestrian traffic deaths by lowering speed limits with traffic calming using road diets. After several stroads were replaced by more efficient roadways in Boston, vehicular fatalities fell from 21 in 2016 to 10 in 2018; simultaneously, pedestrian fatalities halved from 14 to 7. This partial success motivated Bostonian locals to demand the complete elimination of the remaining stroads by implementing better road design.