Stroad

According to Marohn, a stroad is a bad combination of two types of vehicular pathways: it is part street—which he describes as a "complex environment where life in the city happens", with pedestrians, cars, buildings close to the sidewalk for easy accessibility, with many (property) entrances / exits to and from the street, and with spaces for temporary parking and delivery vehicles—and part road, which he describes as a "high-speed connection between two places" with wide lanes and limited entrances and exits, and which are generally straight or have gentle curves.[10]

In essence, Marohn defines a stroad as a high-speed road with many turnoffs, and lacking in safety features.[11][10] In his commentary, Marohn states that stroads do not function well as either a street or a road.[12] According to Marohn, the problem with stroads is that engineering codes tend to emphasize speed and traffic flow rather than safety, so that stroads try to be "all things to all people" but end up failing in every way as a result.[6][13]

Dover and Massengale (2014) stated that the design of roads as highways/motorways was originally modelled on the railroad, namely an efficient connection between two populated places (cities, towns, villages) with a car, while streets formed networks inside a place to move around that place with numerous different modes of transportation to make it financially productive; these two systems functioned well as long they were kept separated,[14]

But when we reconfigure our streets to have the characteristics of roads—as stroads—we are no longer able to capture the value of share the space. A modern stroad ... is about the least safe traffic environment you could be in, too, with high-speed designs mashed up with turning traffic, stop-and-go traffic, sudden lane changes, and obnoxious signage. This ridiculously unsafe design is accepted as "normal" just because it was allowed to become ubiquitous.[14]

They noted that the general public is often not aware of the functional distinction that engineers (as well as dictionaries) make between streets and roads, that street names ending with 'street' or 'road' (for historical reasons) may be misleading and not align with the current de facto traffic situation, and that mixing up the functions of streets and roads causes numerous problems.[15]

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, which went viral, and[10][16]^: 1:02 stated that stroads in North America are "ugly, dangerous, and inefficient", as well as more expensive, contrasting them with road design in the Netherlands, where clear functional distinctions between motorways (highways), roads, and streets were introduced in the 1990s.[17] These measures were aimed at increasing safety, traffic flow, and cost-effectiveness, while also having the effect of reducing car dependency, increasing walkability, cycleability, and general livability.[17] Unlike the two functions ("street" versus "road") proposed by Marohn's foundation Strong Towns,[18] the Dutch Institute for Road Safety Research (Dutch: Stichting Wetenschappelijk Onderzoek Verkeersveiligheid (SWOV), lit. 'Foundation (for the) Scientific Study (of) Traffic Safety') identified three functions for roadways in 1994: flow, distribution, and access.[19][17]

1. Flow roads[20] (Dutch: stroomwegen[21]) are designed to transport lots of people at high speeds.[20] These have been compared to the European and Commonwealth English "motorways" and the U.S. "interstate highways".[20][21]
2. Distributor roads[20] (Dutch: gebiedsontsluitingswegen[22]) are designed to connect flow roads and access roads.[20] They are not meant to give direct access to private property,[20] and roundabouts are the preferred traffic control option rather than traffic lights.[23]
3. Access roads[20] (Dutch: erftoegangswegen[24]) are designed to provide access to private property, such as 'homes, offices, industry, farms, shopping centers, and other similar destinations.'[20] According to William Zurborg (2023), access roads 'only connect to distributor roads, and access roads should be positioned to ensure that they are unattractive to through traffic. Access roads are meant to be characterized by their surroundings, and the road itself is meant to harbor people, not deter them.'[20] The design speed (and speed limit) on access roads is 30 kilometres per hour, or lower.[24] The main road users of access roads are pedestrians, cyclists, and public transport travellers; motorists (car drivers) are made aware of these more vulnerable other road users, to better interact with them, and to take a greater responsibility by slowing down.[20] To aid in keeping vehicular speeds relatively safe, physical forms of traffic calming such as narrowing the streets for motor vehicles may also be employed.[24]
   

The redesigning of roads in the Netherlands into these three functions, as part of the Dutch Sustainable Safety Vision, resulted in a 30% decrease in expected traffic deaths between 1998 and 2007.[20] Zurborg argued that stroads in the United States are the result of local governments designing their roadways to fulfill all three functions simultaneously, thus leading to numerous problems.[25]

In some cases, roads become stroads due to a lack of access management implementation when facilities are expanded or widened, often with the aim of improving mobility. The road becomes a stroad over time from development adding private accessways onto the main road, increasing congestion and collisions, which thus requires traffic control additions such as traffic signals. This degrades the roadway quality in terms of mobility.[26]

Champs-Élysées 1991: road and streets separated

Champs-Élysées 2017: sides pedestrianized

According to Charles Marohn, the famous Champs-Élysées 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-Élysées were physically separated, this stroad environment actually managed some success in allowing both safe high-speed traffic (up to 45 miles per hour (72 km/h)) in the center roadway and a productive street environment on the sides. As of 2019 however, the slip lanes are fully pedestrianized, while the center roadway functions as a true road.[27][6]^: 12:01

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-Élysées 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).[28] He contrasted the Esplanade to Mangrove Avenue, a stroad just five blocks to the east in Chico that runs parallel to the Esplanade, but has all 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.[28]

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".[29] Taking the Nieuwe Dedemsvaartweg (Provincial road N377) outside Nieuwleusen and the Keizer Karelweg (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".[note 1][note 2]

Stroads often do not take into account how human psychology usually determines the speed at which people drive based on the road conditions they observe.[32] Stroads in North America typically have designated speeds between 30 and 45 miles per hour (48 and 72 km/h), but in practice, motorists usually drive 20 to 55 miles per hour (32 to 89 km/h) on stroads.[33] Simply reducing the posted speed limit (PSL) with a traffic sign, which is a widely adopted strategy attempting to prevent motorists from driving dangerously fast, may not work in practice "if the road conditions suggest that the PSL is too low, drivers may simply ignore it".[32]

A better strategy to make people comply with the legal speed limit is to design roads and streets in a way that they are "self-explanatory".[34] Self-explaining roads and streets use physical and perceptual cues (also referred to as traffic calming), which lead people to automatically drive more slowly and cautiously wherever they perceive that to be necessary for their own safety, as well as that of others, especially more vulnerable road users such as pedestrians and cyclists.[35] Such cues 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.[35] The typical lack of these cues on stroads causes motorists to drive much faster than is safe to do in the environment they are in, with many entries and exits creating points of conflict and potential collisions, especially at higher speeds.[35][note 3]

Traffic planners in cities such as Boston,[38] Houston,[39] and St. Louis[6] are rethinking their street designs to lessen collisions and the deaths of pedestrians and cyclists. As of 2019, the city of Boston is studying how to minimize pedestrian traffic deaths by lowering speed limits and redesigning stroads via road diets; the 2018 report from its Vision Zero Coalition suggested that the problem with stroads was that they gave off a false sense that drivers could drive at dangerously fast speeds.[38] 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.[40] This partial success motivated Bostonian locals to demand the complete elimination of the remaining stroads by implementing better road design.[40]

Stroads often lack features designed to make roadways safe for pedestrians, such as crosswalks and adequate street lights. A 2021 report by the Governors Highway Safety Association said that 60.4% of pedestrian fatalities from motor vehicles occurred on such roads.[41]

Although stroads facilitate the goal of making all destinations reachable by car, they also practically force everyone to use (and own) a car, and thus increase car dependency (at the cost of walkability and easy use of public transport), while not necessarily making travelling by car more efficient.[13][9] Despite the high speeds that stroads were designed for, which has made them needlessly dangerous, in practice they frequently end up being clogged with cars seeking access from the many entrances, so that the average speeds on stroads are low due to traffic congestion.[13] Widening stroads to counter congestion usually only leads to induced demand and extra costs.[9]

Typical sidewalk next to a stroad (Route 107 in Lynn, Massachusetts)

The quality of sidewalks (British English: pavement) next to stroads is often poor. Many stroads do not feature any sidewalks at all.[42][43] In the case of stroad-like suburban residential streets, sidewalks are sometimes deliberately left out by design in order "to further the rural image".[13] 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.[44][43] Sometimes there are only "painted sidewalks" next to a strip mall, without curbs or traffic bollards to somewhat protect pedestrians against vehicles that may deviate from the road.[45]

Marohn (2021) stated: "A person on a sidewalk has no defense at all if a vehicle leaves the roadway at stroad speeds".[46] He pointed 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.[47] Marohn was astonished to discover that even a bench had been 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."[47] At intersecting stroads, vehicles often need to decelerate from a high to a low speed to make a sharp turn right at a long turn lane next to a sidewalk; this makes walking there particularly dangerous for pedestrians.[16]^: 1:35 Sidewalks are sometimes too narrow, feature many obstructions such as street lights, as well as driveway cuts, which make them pedestrian-unfriendly.[16]^: 4:35

Middleton (2021) called stroads 'a combination of a people-centric street and a vehicle-centric road'.[43] The stroad space is typical of urban sprawl and car-centric development patterns: it 'seems confused', and is characterized by 'no sidewalk, no shade, and a lot of parking'.[43] 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.'[43]

Walking for a distance of 800 metres (2,600 ft) along a stroad (Farm to Market Road 1960 or Cypress Creek Parkway) in Houston was what motivated Jason Slaughter of Not Just Bikes to wonder who could have possibly designed such a situation, and how urban planning could be done much safer and more efficiently (by improving walkability and reducing car dependency).[48]^: 7:40[49]^{: 4:30, 7:25} 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 (c. 80 to 100 kilometres per hour (50 to 62 mph), creating an extremely unsafe and unpleasant environment for pedestrians.[48]^: 8:36[49]^: 6:03 Yet, the fact that the grass where one would expect a sidewalk was well-trodden, and Google Street View images also showed that people used it, 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.[49]^{: 6:03, 9:14} 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."[49]^: 9:34

Traffic congestion on U.S. 11E in Morristown, Tennessee

Marohn (2017) stated that stroads "are enormously expensive to build and, ultimately, financially unproductive".[35] This is because "stroads are built to a highway standard, their lanes are very wide, and there are never [fewer] than four lanes",[50] or "at least three through lanes",[16]^: 1:49 and they usually take up extra space for shoulders and clear zones.[51] 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.[52][16]^: 3:10 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).[52]

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.[16]^: 2:08 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 asphalt and traffic control system maintenance costs.[53] 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 pale in comparison to urban commercial streets.[13][54]

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).[55] 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, because they cannot sustain themselves.[56]