First Principles for Roadway Design (2000)

Chris Bradshaw, representative for Ottawalk on RMOC committee,
Second Draft, February 20, 2000

The review of Regional Roads Design requires “first principles” that reflect the task at hand and an understanding of how roadways should function.  I base my conclusions on years of driving, cycling, riding-in-transit — but mostly walking — along our regional roads.

A.    The Three Functions of Roadways:

Roads are not just for transportation.  They are for linking the adjacent land uses to each other and to provide opportunities for people to have spontaneous encounters, for start-up entrepreneurs to sell goods and services, and for those with political and cultural concerns to express themselves.  I call this function conviviality.

Also, transportation needs to be divided into two separate functions: access and mobility.  Access is the movement to and from lands along the roads, the original purpose of these rights-of-way.  As trips got longer, mobility received special attention, too often at the expense of accessibility.
These three functions must be in balance on any road.

B.    Road Equality (vs. The Roads Hierarchy)

The only way for all streets to achieve this three-way balance is for all streets to carry traffic, at least in proportion to their right-of-way width.  Street that generate more motor traffic also (or should) generate more walking traffic.  However, this challenges the current “hierarchy” of streets, in which most streets carry only “local traffic” (movements that start or end at properties within a block or two), while the other 10-20% — collectors, arterials, and limited access highways  — carry “through traffic.”

The hierarchy concept has ruined not just the streets at got the heavier traffic, but the others that lost too much traffic to be interesting and to have “eyes” for safety.  It has also made car trips longer, especially for local residents (all trips for suburbanites whose road systems had circuitous patterns installed at the beginning)..

B.    Speed and Safety

It is not surprising that the major outcome of incorporating safety measures on roads has been to increase average and peak speeds (engineers set speed limits at that speed which is beyond what 85% of drivers feel is comfortable).  When safety is increased, individual drivers trade the extra margin of safety to faster speeds, a savings in time, according to a book by Queen’s University professor Gerald Wilde, Target Risk.

Safety has been delivered through the provision of wider lanes, wider roads, safer cars, and ironically “defensive driving” messages (which is a variant of “victim beware”).  The result is that drivers no longer feel responsible for danger caused to others, only the reverse.
The result is that not only do pedestrians and cyclists need to be segregated from motorists, but slower drivers need to be segregated from faster one.  That latter requirement means extra through lanes, plus lanes for turning and accelerating/decelerating.

As overall speeds increase, roads widen to the point that pedestrians can no longer cross safely or have to use signalized intersections that are some distance away.  Also, speed increases require proportionally larger buffer areas between both road users and adjacent areas around and inside buildings.  This use of space imposes a “shadow” on adjacent land uses that sterilize their use by people and even their ability to grow healthy plants.

This “shadow” is one dimension of sprawl; the other is the longer trips that speed makes possible, making trips longer and creating demand for more road space per person, while creating demand for development on more distant lands.

D.     Efficiency

Speed is not a more efficient use of public rights-of-way.  In fact, speed slightly reduces capacity, while greatly reducing the number of road users who can be on the system at any one time.  What is made more efficient is the time of drivers, a private, not a public good.  And because the time of drivers is made more efficient, the value of a car is increased, leading to bigger sales and higher prices by motor companies and related products and services.

But government is supposed to increase the public good, and that means that the rights-of-way should be as efficiently used as possible, while at the same time citizens are provided opportunities for social, economic, and cultural commerce, primarily to sustain that common shared infrastructure, while reducing negative impacts on others.  Thus, it is in the interest of municipal governments that as many trips in as open a way as possible occur on its rights of way.  Movement by car does not meet these goals.

Local governments should be more concerned with under-utilized sidewalks, bike facilities, and bus stops than roads that are not at capacity for motor traffic.

E.    Transportation Freedom

Another important goal for stimulating commerce between its citizens is to ensure freedom of choice.  The current state of our roads hurts “transportation freedom.”  The advertising of cars might emphasize the machine’s power and speed, but these two features either hurt others’ freedom or are met with greater punishment of drivers who are still held accountable.  Speed is usually used to escape from social obligation and conditions such as crime, pollution, and high taxes found in cities.  This is the freedom from, not freedom to.

Rather, it is important to see that walking has the greatest inherent freedom.  The person on foot, due to not posing any inherent danger to others, is not forced to have a license, to have insurance, or to be subject to any but one or two traffic laws.  He is also free of traffic barriers erected for drivers, from the cost of transportation drivers face, and from the bother of finding places to store his means of transportation. [see appendix on the impacts of speed].

G.    Speed Layering:

One of the most important features of any road, including pathways, is “speed layering.”  Since the beginning of building and using of formal thoroughfares, the faster traffic always stayed to the centre, providing a buffer with the fixed objects and slower travellers along the way.  However, as speed have increased, the buffers between the lanes have not increased enough.  Sidewalks directly adjacent to the curb is not appropriate to traffic faster than, say, 25 km/h.  Also, cyclists, not welcome mixed into traffic that has increased in speed since the last time cycling was ubiquitous, have had to create their own lane out of the buffer motor drivers need between curbs, catch basins, and parked cars, and therefore are in harm’s way.  The greater setbacks for buildings is another impact of greater speeds.  Speed layering also must provide for areas for moving into and out of the main flow of traffic.  See CURBBBBB Lanes, at the end, for a way to get the speed-layering features back.

H.    Places vs Spaces: What is the Dividing Line?

There is a magic threshold beyond which places are degraded into spaces.  Places have human meaning and contain the fabric of community life, while space is little more than a buffer between incompatible uses.

I suggest that “placeness” require the following elements:
a)        Speeds of motor cars less than 25 km/h (the speed at which vulnerable road users fear death and serious injury, older children have trouble judging approaching traffic, and cars need to pass cyclists)
b)        Roads no wider than two lanes of moving motor traffic
c)        Curb lanes in excess of two having parking and curb extensions at corners that hold street furniture and people waiting for transit, friends, or to cross the street in an area out of the traveled portion of the sidewalk.
d)        Buildings that face the street and are not set back too far (5-7 metres for residences, no setback for non-residential uses)

H.    Conclusions:

Besides the elements in the previous section, the achievement of “placeness,” “transportation freedom,” and “efficiency” in the use of public rights-of-way will require the following measures:

1.    Better enforcement that will be interpreted as Zero Tolerance.  Enforcement today is too spotty to be seen as a deterrent to offenders or as fair to those caught.  Electronic means show promise of meeting this criterion.

2.    Province should subject all road deaths to inquests (to determine all contributing factors) and should specifically forbid drivers becoming involved in distracting activities..

3.    Road design must reflect the green transportation hierarchy in the official plan.  All expenditures and other measures must result in modal shifts towards walking.

4.    The hierarchy of roads needs to be discarded and all streets required to meet the three functions of mobility, accessibility, and conviviality.

5.    Parking must be moved back to the street, and its provision off the street should be limited (by zoning) and taxes.

6.    Local government must actively coordinate the various transportation modes and develop new options as needed.

7.    The Walking Security Index should be formally instituted as the measure for determining if a streets is a place or a speedway.

CURBBBBB Lanes: A Proposal

Putting all this together, I would propose a pilot project for a neighbourhood.  “CURBBBBB Lanes” is a way to slow traffic and make the roads more socially and physically ecological.  CURBBBB stands for “cars under restrain for bikes, blades, boards, and bus boardings.  It establishes a speed limit half of the current 50 km/h default for all through lanes closest to the curb.  On two-lane roads, the whole road would have a speed limit of 25 km/h, which would be all residential streets and the whole of shopping streets when parking is allowed in the curb (not CURBBBBB lane).  On four-lane roads, the non-curb lanes would have a speed limit of 50 km/h, and on six-lane roads, the two centre lanes would have a limit of 70 km/hr.

What the proposal accomplishes:

1.    Clearly makes residential and high-pedestrian-traffic streets much safer (many of the most vital of these streets already imposes, psychologically, such driver behaviour, e.g., Bank Street in the Glebe, off-peak, and the streets of the Market).

2.    Provides for the growth of the alternative modes and for users to differentiate themselves.  The present method of accommodating cycling (blades and boards are not specifically allowed or banned on roadways) doesn’t allow for growth in volumes, nor a way for slower and faster users to separate themselves.  CURBBBBB Lanes does.

3.    Would eliminate passing on the right.  The ecological principle of “speed layering” is not quite right on our roads, as all lanes of a road have the same speed limit, and the principle of passing on the left has no legal enforcement.  CURBBBBB Lanes provides this.

Appendix A: Speed

Speed imposes costs, on other road users and on the commonweal, as well as on the drivers themselves who supposedly benefit from reduce travel times: [Note: as speed increases, vehicle size also increases over time]

1.    Collisions are more serious
2.    Buffers between road users and within (in the form of safety equipment) must be designed into roads and vehicles (there is still not safety features to protect vulnerable road users).
3.    There is more noise, making conversations between people standing near the road more difficult.
4.    More land beside roads is required to buffer the land use from the negative impacts of speed, and the portions of older buildings and their grounds are increasingly “sterilized” by increases in speed.
5.    Roads surfaces must be designed to higher tolerances, and imperfections must be fixed more quickly, to avoid the punishment to roads and vehicles when tires hit potholes and potholes-to-be.
6.    Road signs and signs on adjacent land uses are increased in size and distance from the “decision point” to accommodate the higher speeds.
7.    Fewer users can “fit” on roads (due to an increased footprint for each user) without congestion “solving” the problem.
8.    Intimidation of slower travelers increases.
9.    The principal advantage of car-use (speed) increases, disadvantaging the alternatives further.
10.    #7 and #8, along with increased speed itself, lead to growth in demand for roadway lane kms in excess of population growth.
11.    Trip lengths over the mid-term increase, as “distances shrink” and drivers choose more distant destinations and later, more remote living arrangements (the latter is to avoid loss of living quality to “others’” driving near their home.
12.    Sight triangles need to be larger (to see the traffic that is approaching the intersection within x seconds);
13.    Turning radii must be increased to allow less loss of speed in turns (which in turn require the construction of the right-turn cut-off that pedestrians and cyclists dread)
14.    Deceleration and acceleration lanes must be longer to get into and out of the main flow of motor traffic (and the speed of motorists crossing the sidewalk and crosswalk increases).
15.    Intersections must be further apart to “pulse” the traffic, to avoid stops, which in turn reduces the number of intersections per km that can be allowed (reducing crossing points for vulnerable users).  This in turn imposes less-direct routes on motorists, and more use of hierarchy of function within adjacent land uses (e.g., service roads, collector roads to parking lots and on which parking is banned; use of stop signs and crosswalks in parking lots, etc.).
16.    Drivers require more of their time spent looking at the road ahead, to the side, and behind.  The trips becomes more stressful and less enjoyable.
17.    The more distant destinations and living arrangements disenfranchise the non-driving members of the household, and reduce quality of life for the poor and disabled (not to mention visitors and those trying to “live lightly”).
18.    The regulatory environment for driving must increase, along with insurance rates, to retain the same accountability and civility that lowers speeds naturally provided (not to mention the effects of “eyes on the street”).
19.    Buyers of cars increasingly ensure their purchase can protect them from others who are traveling faster, or from their own errors when driving faster, e.g., the growth in vans and SUV (both of which also provide a view further ahead on the road, over the tops of sedans, a benefit that is decreasing as so many others also make the same buying choice.)
20.    Congestion, a natural correction for the reduction in road capacity that speed created, increases.


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