Quality and Level of Service(LOS)とは？[HCM 2-2]*1 †
- The Highway Capacity Manual defines levels of service (LOS) as "the LOS is quality measures deescribing operational conditions within a traffic stream and their perception by motorists and passengers."
- The concept of LOS was introduced to qualify the operational characteristics associated with various levels of vehicles or persons passing a given point during a specified time period.
- For this reason, LOS in reality is a qualifier of conditions related to vehicle or person through-put rather than a qualifier of conditions related to individual comfort level.
- Ranges of operating conditions are defined for each type of facility.
- factors:
- speed and travel time（速度、旅行時間）
- freedom to maneuver(操作の自由度)
- comfort/convenience（快適性/利便性）
- traffic interruptions（中断）
- base conditions[HCM 2-3]
- good weather（天候よい）
- good pavement condition（舗装状態はよい）
- users familiar with the facility（その施設に利用者が慣れている）
- no impediment to traffic flow(交通流への妨害がない)
- 評価主体
TYPE OF MODEL
Bicycle Compatibility Index model(BCI) †
- BCI could be used by bicycle coordinators, transportation planners, traffic engineers, and others to evaluate the capability of specific roadways to accommodate both motorists and bicyclists.
- the bicycle compatibility index (BCI) reflects the comfort levels of bicyclists on the basis of observed geometric and operational conditions on a variety of roadways.
- To develop or improve roadways for shared use by these two modes of transportation, one must begin by evaluating existing roadways and determining what is considered "user-friendly" from the perspective of the bicyclist.
- Determining how existing traffic operations and geometric conditions impact a bicyclist’s decision to use or not use a specific roadway is the first step in determining the bicycle compatibility of the roadway.
- 主観性の排除、政策目標（利用者を増やす）を評価する
- The one missing element in each of these studies is ’’the lack of recognition of the bicyclists’ perspectives’’. After all, these are the individuals who will ultimately decide if a roadway meets their personal comfort level for riding in the presence of motor vehicle traffic.
- 開発の経緯*2
- Bicycle Safety Index Rating (BSIR)[1987]
- BRIR=セグメントの安全度+交差点の安全度（セグメントは交差点間で複数あれば加算）
- 対自動車事故+単独事故発生リスクを加法モデル（重回帰）として表現
- セグメントの安全度=交通量+制限速度+幅員+路面状態+セグメント属性（駐車、勾配、カーブ、土地利用）
- 交差点の安全度=流入交通量+(横断困難度)+線形条件(付加車線、視距等)+信号条件
（詳細）セグメントの安全度=日平均交通量(AADT)/(2500×車線数)+制限速度[mph]/35+(14[ft]-W)/2+Σ路面チェック+Σセグメント属性
※数値は0に近い方が安全度が高い(<4:excellent, >6:poor)
※適用地区の変更に伴って係数が変化
- Roadway Condition Index (RCI)[1991]
- an indicator of conditions(not include safety)
- The RCI model to explain only 18 percent of the variation in the crash scores between roadway segments. The first reason for this poor result may simply be the means by which the crash measure was expressed. A much better way to describe the crash would be in terms of "per bicycle miles ridden" or "per number of motor vehicle encounters per mile" or some other exposure measure.
- Interaction Hazard Score (IHS) [1994]
- to overcome two problems noted with the previous models
- 1) the substantial subjectivity used in estimating the values of some of the variables
- 2) the lack of consideration of the exposure variables.
- 変数を２グループに分ける（"longitudinal roadway environment"縦断面環境と"transverse roadway environment"横断面環境）
- The author concludes that the values established for the coefficients and the results of the sensitivity analysis are valid on the basis of interviews with bicyclists and group meetings.
- However, no results from any of these meetings or interviews were provided to assess the actual validity. Thus, it appears that the goal of eliminating subjectivity from the modeling process was not totally achieved within the IHS. It is also not clear whether the goal of increasing consideration for exposure was met. As previously noted, the author did not explicitly define exposure.
- If the goal was to improve the use of bicycle exposure measures within the model, such as bicycle volumes, the model was unsuccessful. However, if exposure was defined as potential hazards to the bicyclist, then the model did tend to include measures that were directly applicable and more objective when compared with previous models.
- Bicycle stress level?[1978]
- This concept was developed, in part, on the assumption that bicyclists not only want to minimize the physical effort required when choosing a roadway on which to ride, but that they also want to minimize the mental effort, or stress, that results from conflict with motor vehicles, interaction with heavy vehicles, and having to concentrate for long periods of time while riding on high-volume and high-speed roadways.
- Bicycle Level of Service (BLOS) model?
- The lack of bicycle exposure data on the roadway segments was the principal reason noted by the authors in explaining the poor results of the analysis
the inclusion of the term pavement condition in the BLOS model.
The developers of the model insist that this variable is critical to determining the quality of service for bicyclists. The authors of this report do not disagree with that statement, but take the position that bicycle routes should not be established on the basis of that criterion. Instead, the geometric and operations variables identified as significant in the BCI model should be used for establishing bicycle level of service and subsequently appropriate routes. The surface quality of those routes on the bicycle network should then be maintained to minimize hazards and provide a quality ride for bicyclists.
- factors
These main requirements are safety, coherence, directness, comfort, and attractiveness. Not complying with these requirements may result in a situation where cycling is not as attractive as is could be.
- Safety:
For large parts of the population in Europe (the perception of) road safety problems is a key factor for not cycling. Improving the safety of cyclists on the road is therefore a precondition for cycle promotion. Whereas the scope of the PROMISING project is the promotion of safety, it will be the other four main requirements that provide the basis for restrictiveness assessment; i.e. our assessment will look at conflicts between the safety requirement and the
other main requirements.
- Coherence:
Criteria for coherence are continuity, consistency of quality, recognizability and completeness. It is obvious that cycling will be restricted if the cycle network is not complete or coherent. These are mainly features on the network level.
- Directness:
Criteria are mean travel time, delays, and detours. Any safety measure resulting in extended travel time, such as detours or delays are considered to be restrictive.
- Comfort:
Criteria are smoothness of road surface, curving, gradients, number of stops between origin and destination, and complexity of rider’s task. This criterion is relevant indeed, when it comes to judging the restrictiveness of road safety measures. Introducing narrow or sharp (uncomfortable to ride) curves, extra stops, and adding to the complexity of the rider’s task, is considered to be restrictive.
- Attractiveness:
Criteria are visual quality of the road, overview, variety of environment, and social safety. Road safety measures might result in less visual quality and more (perceived) social insecurity, and thus be restrictive.
- Subjective character of judgement:
When judging restrictiveness, the experience or perception of cyclists is important and should be decisive. If cyclists don't like the measure, then the measure for these cyclists is in fact restrictive.
- LOSの初期は自転車事故モデルでその流れを結構引きずっていることがわかる -- よしだ?
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