A survey of operational definitions of hazardous road locations in some European countries

This paper presents the results of a survey of operational definitions of hazardous road locations in some European countries. The term operational definition refers to the criteria and methods used to identify hazardous road locations. Eight countries were included in the survey. The operational definitions of hazardous road locations used in these countries were compared in terms of six characteristics:

• 1. 

  Whether hazardous road locations are identified by reference to a population of similar sites, i.e. by means of sampling from a predefined list of sites or identified without referring to any population of sites.

• 2. 

  Whether a sliding window method is used to identify hazardous road locations.

• 3. 

  Whether hazardous road locations are identified in terms of deviance from a normal level of safety or without reference to a normal level of safety.

• 4. 

  Whether hazardous road locations are identified in terms of the recorded or expected number of accidents.

• 5. 

  Whether accident severity is considered in identifying hazardous road locations or not.

• 6. 

  The length of the period used to identify hazardous road locations.

Most operational definitions of hazardous road locations were found: (1) not to refer to any population of similar sites, (2) to rely on a sliding window approach, and (3) identify hazardous road locations in terms of the recorded number of accidents. In four of the countries, hazardous road locations are identified as sites that have significantly more accidents than the normal number. Accident severity was considered in four of the countries. The period used to identify hazardous road locations varied between 1 and 5 years.Compared to state-of-the-art techniques for identifying hazardous road locations, most of the approaches used in the countries surveyed were primitive and are likely to involve substantial inaccuracies. Steps that can be taken to bring practice closer to the state-of-the-art are outlined.     

An approach to the application of subjective probabilities in level 2 PSAs

Accident Progression Event Trees are commonly used in Probabilistic Safety Assessments (PSAs) for nuclear power plants, chemical process plants and offshore installations. Their quantification necessitates the application of subjective probabilities in dealing with certain issues, such as physical phenomena. Although the subjective probability concept has been widely used in PSAs, its acceptability remains questionable mainly due to the current lack of formalism in the process of subjective probability derivation. A procedure was developed for the Sizewell ‘B’ Level 2 PSA to improve the traceability and scrutability of this process. The key elements include:

• • 

  • development of a degree of belief scheme

• • 

  • issue decomposition

• • 

  • supporting data derivation

• • 

  • documentation route.

A brief discussion of this procedure and two illustrations are provided in this paper.     

Use of reliability technology in the process industry

Reliability analysis has been established as a useful tool for risk analysis and the design of safety systems. During the past ten years use of advanced methods for optimal maintenance and process control based on reliability technology has been introduced. Lack of data has been a problem, but even more important has been the reluctance of personnel involved with regard to implementation of these methods. One reason for this is the complexity of the models and methods presented. In the future more emphasis should be put on the solving of problems as experienced by the industry. The following are proposed to encourage the use of reliability technology:

• &;#x02022; 

  close cooperation with industry;

• &;#x02022; 

  focus on specific problems as experienced by the industry rather than system modelling;

• &;#x02022; 

  development of simple methods to be applied by the people who own the problem.

     

The predictive validity of empirical Bayes estimates of road safety

This paper examines the predictive validity of empirical Bayes (EB) estimates of road safety. The predictive performance of EB-estimates was tested by applying five versions of EB-estimates of road safety:

• (1) 

  A simple estimate derived from the empirical distribution of accidents in a population of sites, by which the number of accidents predicted for period 2 for sites that recorded k accidents in period 1 equals the number of accidents for sites that recorded k + 1 accidents in period 1.

• (2) 

  Estimates derived from the parameters of a negative binomial distribution fitted to an empirical distribution of accidents in a population of sites by means of the method of moments.

• (3) 

  Estimates derived from the parameters of a negative binomial distribution fitted to an empirical distribution of accidents in a population of sites by means of the maximum likelihood technique.

• (4) 

  Estimates derived by combining the predictions of an accident prediction model and the recorded number of accidents for a site.

• (5) 

  Estimates derived by combining the predictions of a different version of an accident prediction model and the recorded number of accidents for a site.

All versions of EB-estimates are compared to the traditional, naïve assumption of treating the recorded number of accidents as an unbiased estimate of the expected number of accidents.To test the predictive performance of EB-estimates, data for two periods was used. EB-estimates based on data for the first period were treated as predictions of the number of accidents in the second period for road sections that had 0, 1, 2, etc., accidents in the first period, the idea being that the more accurate the prediction, the more accurate the result of a before-and-after study.All versions of EB-estimates were found to give considerably more correct predictions of the number of accidents in the second period than relying on the count of accidents in the first period as a prediction of the count in the second period. Smaller prediction errors were associated with predictions based on accident prediction models than predictions not based on such models.     

Characteristics of single vehicle rollover fatalities in three Australian states (2000-2007)

An analysis of 2000–2007 single vehicle rollover fatalities in three Australian states was carried out using data from the Australian National Coroners Information System. In this paper, successive selection criteria were applied to the initial dataset to analyse:

• - 

  Occupant fatalities in single passenger car crashes (1743 cases),

• - 

  Occupant fatalities in single passenger car rollovers (474 cases),

overall, rollovers accounted for 35% of all occupant fatalities in a single vehicle transport injury event. For these fatalities, the occupant was ejected or stayed contained in equal proportions. However, results showed strong disparities between the more urban and densely populated states of New South Wales and Victoria, compared to the Northern Territory in terms of crash type distribution and containment of the occupant. Differences were also found in rollover initiation, speed at initiation and number of turns. Overall, the strongest association of fatal neck/thoracic spine injuries with head injuries was found for the contained, restrained occupant. This analysis of single vehicle rollover fatalities is consistent with previous findings. It also shows that in Australia, strategies for rollover injury risk mitigation will need to take into account a broad range of characteristics to be effective.     

Supplementary Zeeman Data for the First Spectrum of Ruthenium (Ru I)

Zeeman data are listed for 207 lines of Ru I between 2400 and 5400 A, all of which have been classified. The spectrograms were made at the Massachusetts Institute of Technology and were analyzed there and at the National Bureau of Standards.Harrison and McNally² published Zeeman data for 450 lines of the first spectrum of ruthenium (Ru I) in 1940. In addition unresolved patterns were measured by McNally for 175 lines, but these have never been published.³ Further Zeeman observations were made in 1949 by Meggers with the Bitter magnet at the Massachusetts Institute of Technology. These plates were measured by Kessler in the course of preparing material for the preceding paper. Zeeman data for 32 additional lines obtained from this last set of observations, together with the unpublished material from McNally’s thesis for 175 lines are listed below.The observations were all made with electrodes of 1 part ruthenium powder mixed with 5 parts of silver powder. The experimental conditions and techniques used are fully described by Harrison and McNally.²The wavelengths (in air) of these lines are given in column 1 of

A Preliminary List of Levels and g-Values for the First Spectrum of Thorium (Th I)

The present state of the analysis of the first spectrum of thorium (Th I) is discussed briefly. Even and odd levels are listed in ​and2.2. The low even levels form terms arising from the configurations 6d² 7s² and 6d³ 7s. The Th I standard wavelengths that fit into the known level arrays are presented in Config.DesignJLevelObs. gLS. g

---

---

---

---

---

---

6d²7s²a ³F2  0.000.7410.6673  2869.261.0741.0834  4961.661.2121.250a ³P0  2558.060.00   0/01  3865.471.4771.5002  3687.991.2561.500a ¹D2  7280.131.1891.000a ¹G4  8111.001.08  1.0006d³(⁴F)7sa⁵ F1  5563.140.0620.0002  6362.401.0141.0003  7502.291.2531.2506d³(⁴F)7sa ⁵F4  8800.251.3101.3505  9804.811.3661.4006d³(⁴P)7sa ⁵P111601.032.41  2.500211802.941.7211.833312847.971.39  1.6676d³ (²G)7sa ³G313088.571.04  0.750413297.420.98  1.050514204.301.13  1.2006d³ (²D)7sa ³D113962.500.76  0.5006d³(²H)7sa ³H415493.230.92  0.800Open in a separate window

Table 2

Odd energy levels of Th I

CH in the Solar Spectrum

CH lines in the solar spectrum have been identified by direct comparison of measured laboratory and solar wavelengths and intensities. The comparisons of individual rotational lines are included in a series of tables arranged according to electronic and vibrational transitions.A detailed investigation of the presence of CH lines in the solar spectrum has been carried out recently as part of the preparation of a current edition of solar spectrum data to replace the 1928 compendium [1].¹ Along with the study of atomic lines, a parallel survey of molecules in the sun is required for any complete revision of the “Solar Spectrum.” A preliminary résumé of the number of CH, OH, and CN lines in the solar spectrum was recently published [2].Many lines of CH are familiar features in the solar spectrum. In his original table, Rowland [3] attributed some of these lines to “C,” and numerous CH lines were included in the 1928 edition [1]. Several authors have carried the work further. For example, Hunaerts [4] and Richardson [5] have each published a list of solar lines which may be ascribed to CH.The present results are based on a study of the rotational structure of individual bands, together with relative laboratory intensities measured along the different branches. It reveals more CH lines in the sun than have been recognized heretofore. A summary of the counts is included in 2] they referred to solar lines. Consequently, if two CH lines contribute to one solar line, each CH line is counted here as a blend. Exception has been made in the case of Table No.Laboratory

---

Sun

---

Electronic transitionVibrational transitionWavelength range ATotal number linesReferencesStrongest solar int. Δλ/λSummary of counts

---

PresentBlendMaskedAbsentTotal

---

  2A ²Δ–X ²Π0, 04133 to 4413309639.6155924616309  31, 14185 to 4446235624.370687215225  42, 24238 to 4468188626.65436618159  50, 14726 to 494119870.65314931  61, 24741 to 4913149700

---

Total1,07928419919348724  7B ²Σ⁻— X ²Π0, 03871 to 4084106649.44341202106  81, 03627 to 371054613181022454  91, 14025 to 41195067.6161122150

---

Total210Rowl. est.776264721010C ²Σ⁺—X ²Π0, 03086 to 3219119±8[2]314118696111, 13119 to 3222508[0]81324550

---

Total169±39544211146Open in a separate window

Table 5

CH in the Solar Spectrum A ²Δ—X ²Π (0, 1)

Ionization Constants of the Six Dichloroanilines and the Six Dichlorophenols in Aqueous Solution at 25 °C

The thermodynamic ionization constants of the six dichloroanilines and the six dichlorophenols in aqueous solution at 25 °C have been determined by the spectrophotometric method. The pK values found are recorded in pKΔpK(1)ΔpK_A(2)

---

---

---

DichloroanilineDichlorophenolDinitrophenolDichlorophenolDichloroaniline2,3–1.76₁(0.005)7.69₆(0.006)0.65−0.050.16−0.02₆2,4–2.01₆(.004)7.89₂ (0.005)  .25    .06  .01  −.00₆2,5–1.52₉(.003)7.50₈ (.005)  .40    .15  .03  −.05₇2,6–0.42₂ (.004)6.79₁(.003)  .71    .27  .28     .04₅3, 4–2.96₈(.005)8.58₅ (.006)  .13  −.04−.07     .01₃3, 5–2.38₃(.003)8.18₅(.004)  .11    .07   .06     .03₇Open in a separate window^aΔpK(1)=pK (calc.)−pK (obs.), pK (calc.) being calculated from pK values of the monosubstituted compounds. ΔpK_A (2)≡pK_A (calc.)−pK_A (obs.), pK_A (calc.) being calculated by eq (6).An approximately linear relation is found to exist between the pK_A value of a dichloroaniline and the pK_P value of the corresponding dichlorophenol. The relation is pK_A = ?9.047 + 1.401 pK_P.This equation yields pK_A values which differ from the observed by not more than 0.06 pK unit and, on the average, by 0.03 pK unit; it applies even when both substituents are in the ortho position.