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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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    <item>
      <title>THE CONDUCT OF ROAD MAINTENANCE IN GHANA</title>
      <link>https://trid.trb.org/View/202718</link>
      <description><![CDATA[A study has been conducted of road maintenance in Ghana. This is a report of the part of the study that was concerned with the accomplishment of various road maintenance activities and the effectiveness of the utilisation of the different resources devoted to those activities.  Field observations have been made of the conduct of the main maintenance activities.  Overall accomplishment was much less than programmed for most activities.  Measurements showed that rates of output in equipment-based activities were poor because the availability and utilisation rates of mechanical plant were extremely low.  In those labour-based activities for which transport was required outputs were also low, due to poor availability of vehicles.  It is concluded that more reliance on labour-based techniques for routine maintenance would be advantageous.  At present the very limited capacity to support mechanical plant severely constrains the effective use of that plant.  The use of mechanical equipment would thus best be concentrated on those maintenance activities for which there is no practical alternative technique.  (Author/TRRL)]]></description>
      <pubDate>Wed, 30 May 2001 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/202718</guid>
    </item>
    <item>
      <title>A SURVEY OF ATTITUDES TO CAR SHARING: A DATABASE FOR MICROSIMULATION</title>
      <link>https://trid.trb.org/View/325948</link>
      <description><![CDATA[No abstract provided.]]></description>
      <pubDate>Mon, 30 Apr 1990 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/325948</guid>
    </item>
    <item>
      <title>THE RURAL TRANSPORT EXPERIMENTS: PROCEEDINGS OF A SYMPOSIUM HELD AT THE TRANSPORT AND ROAD RESEARCH LABORATORY, CROWTHORNE, ON 8 NOVE</title>
      <link>https://trid.trb.org/View/325755</link>
      <description><![CDATA[No abstract provided.]]></description>
      <pubDate>Sat, 31 Mar 1990 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/325755</guid>
    </item>
    <item>
      <title>THE USE OF PULVERISED FUEL ASH IN LEAN CONCRETE ROADBASES. PART 2: PILOT-SCALE TRIALS</title>
      <link>https://trid.trb.org/View/270239</link>
      <description><![CDATA[Pilot-scale trials were laid to investigate the properties of roller-compacted lean concrete roadbases in which pulverised fuel ash was included as a partial replacement for some of the cement.  A conventional lean concrete and a cement-rich concrete were included in the trials for comparison.  Structural performance was assessed by measuring strain and deflection under a moving wheel and elastic modulus by surface wave propagation.  Beam specimens cast in moulds and cut from the trial area were used to determine stress-strain relationships, flexural strength and elastic modulus.  The measured transient deflections and strains in the ash-modified lean concrete pavements were similar to those in the conventional lean concrete; the values of elastic modulus were also similar. Results from the beams showed that in general the ash-modified mixes have a lower early life strength and a higher long term strength than conventional lean concrete. An analytical study suggested that both ash-modified lean concrete with a low early life strength and conventional lean concrete may suffer from microcracking when trafficked by construction vehicles at 7 days old but visible cracking should not occur.  The overall structural behaviour of the pilot-scale trials was sufficiently encouraging to recommend a full-scale trial of ash-modified lean concrete. (Author/TRRL)]]></description>
      <pubDate>Sat, 31 May 1986 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/270239</guid>
    </item>
    <item>
      <title>THE USE OF PULVERISED FUEL ASH IN LEAN CONCRETE ROADBASES. PART 3: FIELD STUDIES</title>
      <link>https://trid.trb.org/View/270240</link>
      <description><![CDATA[This report is the third in a series that describes research to assess the performance of lean concrete roadbases modified by the addition of pulverised fuel ash (pfa). Field trials in which the performances of conventional lean concrete, a cement-rich concrete roadbase and ash-modified lean concrete were investigated confirmed earlier work on the modifications to the strength/age characteristics and the improved compactability brought about by the addition of PFA.  In addition the trials showed that the development of thermal cracking in concrete roadbases was dependent on the early strength of the material.  Trafficking the roadbases when they were seven days old showed that provided the materials met current specifications for cement-bound roadbases no additional cracking should occur as a result of the trafficking.  It was concluded that ash-modified lean concrete may, with advantage, be used as a replacement for conventional lean concrete providing it meets existing specifications for cement-bound roadbases.  (Author/TRRL)]]></description>
      <pubDate>Sat, 31 May 1986 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/270240</guid>
    </item>
    <item>
      <title>THE TRRL HIGH-SPEED ROAD MONITOR: ASSESSING THE SERVICABILITY OF ROADS, BRIDGES AND AIRFIELDS</title>
      <link>https://trid.trb.org/View/270245</link>
      <description><![CDATA[Conventional methods of measuring road surface characteristics that affect serviceability are slow and disrupt normal traffic flow.  This report describes the use of a high-speed road monitor to measure the surface characeristics of roads, bridges and airfields at normal road traffic speeds.  The equipment measures longitudinal profile, wheel-track rutting, texture depth and concrete groove dimensions; provision is being made for the measurement of road crossfall, gradient and horizontal curvature.  Data is stored in digital form on floppy disc and can be processed on board the vehicle or transferred to a main frame computer for more detailed analysis.  Examples of applications include the evaluation of riding quality on new and in-service roads and the monitoring of changes caused by subsidence, the detection of changes in suspension bridge shape, and movement of slabs in concrete roads. Profile data are also used for the calculation of road surface unevenness spectra and the detection of systematic surface unevenness.  (Author/TRRL)]]></description>
      <pubDate>Sat, 31 May 1986 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/270245</guid>
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    <item>
      <title>SPECIFICATION FOR THE TRRL FROST-HEAVE TEST</title>
      <link>https://trid.trb.org/View/217415</link>
      <description><![CDATA[The TRRL frost-heave test is nominated in the Department of Transport's specification for road and bridge works to establish the degree of frost-susceptibility of unbound sub-base and base materials.  The test as originally described in LR 90 contained insufficient detail for it to be carried out in a standardised manner with granular materials.  This led to problems both in carrying out the test and in the interpretation of results; the laboratory therefore undertook a research programme to improve the test.  This work has now been completed and this report contains a specification for an improved test procedure that has been developed from the results of the research. This procedure supersedes that given in LR 90 and other publications of the laboratory which give details of the Test.  (Author/TRRL)]]></description>
      <pubDate>Fri, 31 Jan 1986 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/217415</guid>
    </item>
    <item>
      <title>RESULTS FROM THE M1 (LUTTERWORTH) AXLE WEIGHT SURVEY (1982)</title>
      <link>https://trid.trb.org/View/217416</link>
      <description><![CDATA[In 1982 a random sample of 1408 goods vehicles (at least 3.5 tonnes gross weight) was selected from the southbound M1 near Junction 20, the Lutterworth exit, for a roadside survey.  In addition three "special types" goods vehicles were surveyed and all 1411 vehicles were weighed and measured.  This report summarises the data collected and assesses the extent and the effect of overloading.  It was found that 15 per cent of the 1408 goods vehicles were overloaded accounting for 5.2 per cent of road damage on the M1.  The three "special types" vehicles accounted for 0.6 per cent of the road damage on the M1.  If operators had used a smaller number of fully, but legally loaded vehicles to carry the same loads, road damage could have been 18 per cent greater than measured.  (Author/TRRL)]]></description>
      <pubDate>Fri, 31 Jan 1986 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/217416</guid>
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    <item>
      <title>COMPARISON OF FIXED TIME AND FLEXIBLE PROGRESSIVE TRAFFIC CONTROL IN SLOUGH</title>
      <link>https://trid.trb.org/View/217417</link>
      <description><![CDATA[Since 1977 Slough Borouch Council have operated a compact urban traffic control (utc) system in which a central computer coordinates the timings of traffic signals in slough.  The signals are controlled by a flexible progressive system in which the central computer allows the timings to vary by a few seconds from the present" fixed time plans" which maintain coordination.  The variations in timings are determined by the presence or absence of vehicles over stop-line detector loops; similar systems have been used for many years at other sites.  In spring 1983, the TRRL conducted a survey to compare the flexible progressive system with a fixed time system that used the same coordination plans.  A "floating car" survey method was used to measure journey times along the A4 Bath road and A355 Farnham road during four periods of the day for five weeks in spring 1983.  The results show no significant differences in journey times measured with the two control systems, although there is some indication that the flexible progressive system gives slightly shorter journey times in the morning peak.  It is possible that the flexible progressive control system can adapt to small changes in flow, and so reduce the need for updating the fixed time plans.  (Author/TRRL)]]></description>
      <pubDate>Fri, 31 Jan 1986 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/217417</guid>
    </item>
    <item>
      <title>EXHAUST EMISSION FROM CARS IN SERVICE-CHANGES WITH AMENDMENTS TO ECE REGULATION 15</title>
      <link>https://trid.trb.org/View/217418</link>
      <description><![CDATA[A number of surveys of emissions from cars in service have been carried out and an analysis has been made of the emissions from vehicles built to the various amendments to ECE regulation 15 in order to discover whether the downward trend in type approval limits has produced lower emissions in practice.  The range of emissions measured in the surveys was wide, but the mean values for the "tuned" vehicles complied in most cases with the type approval limits appropriate to the vehicle.  The type approval limits were most easily met for the emissions of the oxides of nitrogen; more difficulty was found with the other pollutants. Statistical analysis of the data, comparing emissions from 03-amendment vehicles with others showed that only about one-third of the comparisons had a high probability of being significantly different.  But the variability of the data and small sample sizes obscure the downward trend in the mean emissions of carbon monoxide and hydrocarbons from "tuned" vehicles, which were comparable to the reductions in the type approval limits.  More detailed study of emissions at diferent road speeds has shown that the ECE regulation 15 test cycle represents the higher concentrations of carbon monoxide and hyrocarbons, with concentrations falling rapidly at higher average speeds, and a reasonable estimate of oxides of nitrogen levels except for high-speed motoring. Modes of operating, other than a steady speed, are likely to produce higher emissions with high rates of acceleration giving very high emissions.  The more detailed study of a vehicle between service intervals shows considerable increase in carbon monoxide and hydrocarbon concentrations, with servicing reducing emissions to meet the approved level again.  (Author/TRRL)]]></description>
      <pubDate>Fri, 31 Jan 1986 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/217418</guid>
    </item>
    <item>
      <title>COMPARISON OF FIXED TIME AND FLEXIBLE PROGRESSIVE TRAFFIC CONTROL IN SLOUGH BY C.J. LINES AND C.F. LUCAS</title>
      <link>https://trid.trb.org/View/222422</link>
      <description><![CDATA[No abstract provided.]]></description>
      <pubDate>Thu, 31 Oct 1985 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/222422</guid>
    </item>
    <item>
      <title>AN ANALYSIS OF POLICE AND MEDICAL ROAD ACCIDENT DATA : SRI LANKA 1977-81</title>
      <link>https://trid.trb.org/View/222423</link>
      <description><![CDATA[No abstract provided.]]></description>
      <pubDate>Thu, 31 Oct 1985 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/222423</guid>
    </item>
    <item>
      <title>ROAD ACCIDENTS IN DEVELOPING COUNTRIES : URBAN PROBLEMS AND REMEDIAL MEASURES</title>
      <link>https://trid.trb.org/View/222424</link>
      <description><![CDATA[No abstract provided.]]></description>
      <pubDate>Thu, 31 Oct 1985 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/222424</guid>
    </item>
    <item>
      <title>GEOMETRIC DELAY AT NON-SIGNALISED INTERSECTIONS</title>
      <link>https://trid.trb.org/View/209376</link>
      <description><![CDATA[Four separate studies of "geometric delays" at a range of non-signalised intersections have been carried out during the past six years by the Transportation Research Group at Southampton University, under contract to the Transport and Road Research Laboratory (TRRL) and the Department of Transport (DTP).  The term "geometric delay"  has been used to describe the extra time required by vehicles as they slow to negotiate an intersection.  In the early studies at roundabouts and priority junctions, relationships were developed for geometric delay based on category analysis and linear regression techniques.  In the later studies, however, more exphasis was put on the development of a synthetic model to simulate the speed profiles of vehicles as they negotiated the intersections.  Relationships were developed for parameters such as minimum speeds and acceleration/deceleration rates, these relationships being based on readily measureable dynamic or geometric variables. The synthetic model has been extended so that it is now applicable to all forms of non-signalised intersections giving estimates of journey time as well as delay.  The form and application of the model is described in detail in this report.  The main features found to affect geometric delay are: (1) the extra distance which has to be travelled compared with the no-junction alternative; (2) the speed drop that occurs between the approach/exit roads and the internal sections of the intersection.  (Author/TRRL)]]></description>
      <pubDate>Wed, 30 Oct 1985 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/209376</guid>
    </item>
    <item>
      <title>EVALUATION OF PEDAL CYCLE SPACERS</title>
      <link>https://trid.trb.org/View/209377</link>
      <description><![CDATA[Devices, commonly called "spacers" (attached to the bicycle to discourage drivers from passing too close to the cyclist when overtaking) have been evaluated.  Commercially available spacers usually consist of a plastic rod with either a flag of disc attached at the end.  The overall length is about 0.4M.  Spacers are usually mounted horizontally on the rear offside of the bicycle so that they project toward overtaking traffic.  They are widely used in Scandinavia but have only recently gained acceptance in the UK.  By employing a specially developed ultrasonic ranging technique that allowed the easy measurement and recording of large numbers of gaps left by drivers overtaking a test cyclist it was possible to quantify precisely the effects of spacers of various types of drivers' overtaking behaviour. Measurements were taken on a variety of roads during the day and night.  Results show that the percentage of overtaking vehicles passing less than 0.8M from a test cyclist was approximately halved when using a spacer 0.5M.  In length. A spacer 0.35M long was only about half as effective.  The effects of the 0.5M long spacer were shown to be very similar to that of a fluorescent yellow jacket for discouraging close overtaking.  (TRRL)]]></description>
      <pubDate>Wed, 30 Oct 1985 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/209377</guid>
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