Level of service – a concept past its sell by date?

In August 2014 the Streetsblog website published an article (here) which began:

Ding, dong…LOS is dead.
At least as far as the state of California is concerned.

The article went on to say:

Level of Service (LOS) has been the standard by which the state measures the transportation impacts of major developments and changes to roads. Level of Service is basically a measurement of how many cars can be pushed through an intersection in a given time. If a project reduced a road’s Level of Service it was considered bad — no matter how many other benefits the project might create (own emphasis)


Now, thanks to legislation passed last year and a yearlong effort by the Governor’s Office of Planning and Research (OPR), California will no longer consider “bad” LOS a problem that needs fixing under the California Environmental Quality Act (CEQA) . This won’t just lead to good projects being approved more quickly and easily, but also to better mitigation measures for transportation impacts.

What is level of service?

The 2001 publication by the SATCC (ref. 771) explained the concept of Level of Service as:

The concept of Level of Service (LoS) is a qualitative measure describing operational conditions within a traffic stream and their perception by drivers and/or passengers. A Level of Service definition generally describes these conditions in terms of such factors as speed and travel time, freedom to manoeuvre, traffic interruptions, comfort, convenience and safety. Six levels are defined for each type of facility ranging from LoS A, which is the highest level to LoS F which is the lowest and subject to instability and total breakdown of flow. The capacity of a road is defined as the volume of traffic associated with Level of Service E. Level of Service B. Level of Service B is usually selected for design purposes.

 level of service

You can see from the chart that Level of Service B is nowhere near peak capacity, which arguably still appears at a reasonable speed (from the chart, 2800 pcu/hr and 75 km/h).

Level of service and public transport

In September 2014 various newspapers in the UK reported on the Department for Transport’s list of the most crowded trains in England and Wales for 2014. For example the BBC website said (here):

Top of the list is a train originating in Scotland, the 04:22 TransPennine Express service from Glasgow Central to Manchester Airport. At its peak, 355 people were counted on a train designed for 191.


So from the above notes it looks like transport planners design motorways with lots of comfort and a designed under-capacity of 28% (800/2800), whilst passengers on public transport have to accept an over-capacity of 85%.

The newspaper the Independent, in an article on the Department of Transport list, quoted Martin Abrams, Public Transport Campaigner, Campaign for Better Transport, who said:

“Overcrowding is becoming unbearable for rail users across the UK. Almost a quarter of passengers are now forced to stand on the busiest commuter routes and people will be asking, why the quality of their service and passenger experience is declining when fares have increased so steeply over the last five years?”

If an acceptable value of LoS for main roads allows plenty of spare capacity, then the same should be applied to other transport modes, such as public transport. Certainly the basic planning principles should be the same – otherwise people might begin to think that the whole transport planning concept is strongly biased towards roads and cars.

I believe that the Level of Service concept may also be included in the decision-making process which recommends values for a number of geometric design parameters, such as maximum gradient. Does California’s apparent rejection of the LoS concept mean that – for example – the recommended values for maximum gradient now have to be revised?


771 – South Africa, SADC / SATCC “Draft code of practice for the geometric design of trunk roads”, 2001


About roadnotes

Robert Bartlett is an international consultant with over 30 years of professional experience as a highway and traffic engineer with leading companies and organisations in several countries, including Germany, China (Hong Kong), Qatar and the UK. Specialised in urban studies, transport and the use of GIS, research has included new ideas on subjects such as the study of social justice using GIS, the dimensions of vehicles, and comparative geometrics (highways and transport).
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3 Responses to Level of service – a concept past its sell by date?

  1. Pedro says:

    I think that even a project could bring other benefits than a good LOS it will not be perceived by users stucked in traffic jams. Could you imagine a newly inaugurated enlargement of a road with LOS D?. User would think that the work was a wasting of money

  2. roadnotes says:

    Hi Pedro. Maybe LOS D would be accepted if it were only in the peak hours. Central London’s roads are probably LOS F during much of the day. I think maybe the California move is towards more integrated transport planning. So that if a choice was to be between a road with LOS A and train improvements from (say) LOS F to LOS D, the money should be spent on the train projects. Taking California’s ideas together with growing interest in Europe for bicycle expressways, perhaps there is a wider trend away from people thinking that “individual transport = cars”

  3. Pedro says:

    Hello Robert By this point of view I agree. I was thinkink according to the Brazil reality.
    Here seems that they never choose for an option to incentivate mass transports.

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