Traditionally, the quality-of-service assessment of a roundabout is only focused on the capacity of the individual entries. However, the exits also have an important impact on the performance of a roundabout since they can be temporarily blocked by prioritized crossing pedestrians. As a consequence, exiting vehicles may spill back from the blocked pedestrian crossing onto the circular roadway. At single-lane roundabouts this will cause a queue on the circle, which again can block the upstream entries and reduce their capacity. The extent of this effect is influenced by vehicle traffic volumes, pedestrian volumes, and also the geometric design of the specific roundabout. In practice, an analytical method would be desirable to estimate the effects of this phenomenon. This paper presents such a solution. As a starting point a mathematical model based on queuing theory is developed which calculates the probability of an entry to the roundabout being obstructed by a queue originating from the next exit downstream. This probability is applied to reduce the usual estimated capacity of the entry. The theoretical model is compared with microscopic simulations of a single-lane roundabout. As a result, a high correspondence between the theoretical approach and the simulation, along with a measurement at a real-world roundabout, becomes evident. Therefore, the model is recommended for practical application in, for example, the Highway Capacity Manual (HCM) or the German Highway Capacity Manual (HBS). A set of graphs is presented which can be introduced into such a standardized calculation procedure.

In contrast to conventional methods, this study took a holistic approach to investigating roundabout capacity. Conventional methods aim to identify the capacities of each single entrance, without any consideration of mutual interactions between all the entrances and exits of the roundabout. This study investigated the interrelationships between traffic operations at the elements of a single-lane roundabout based on probabilistic considerations obtained from queueing theory. Here the spread of potential congestion on the circle plays a decisive role. As a starting point, the elements of the roundabout were defined as points of conflict. Equations for the capacity of these points were then derived. These equations were combined into an iterative procedure that took into account the potential congestion on the circle. As a result, based on a given origin–destination matrix of traffic volumes, the entry capacities of the roundabout were calculated. These were then applied to calculate estimates for delays and queue lengths in the conventional way. Application of the model for several examples—two of which are described in this paper—showed rather drastically that conventional evaluations of traffic performance at roundabouts may be misleading, with overestimated capacity and underestimated delays. This happens preferably in a range with volume/capacity values above 0.7 and under significant pedestrian traffic. The study underlines that the current assessment methods of analytical performance at roundabouts fall short.

Under specific circumstances signal timing at a traffic signal allows the switching of two green times within one cycle. Practitioners expect a reduction in delays and queue length as a result of this control strategy. However, no analytical methodology is available to quantify this effect. To resolve this deficit, analytical considerations have been undertaken. They follow the principles that are also the basis for conventional signal performance analysis. The basic difference compared with a single green is that, within each cycle, the maximum length of the vehicle queue remains shorter under the two-green regime. This effect is expressed by the term uniform delay, w1. For that parameter, a specific deterministic derivation is proposed. The second element is the incremental delay, w2, which stands for the effects of randomness and temporary oversaturation. The analysis confirmed that this parameter could be adopted from conventional methods. Different formulas for the estimation of w2 were investigated using simulation studies. Thus, a set of equations is given for the prediction of average delay and of percentile queue length in the case of two green times. Verification of the derived formulas was performed using Monte Carlo simulations. The results could easily be applied in practice and might be implemented into guidelines. The application demonstrated how a second green within one signal cycle reduced delays and, notably, queue lengths.

A method to describe traffic flow at a road junction is the application of a special form of the fundamental diagram (FD). This intersection fundamental diagram (IFD) is an intermediate version between the traditional FD for a single road section and the macroscopic fundamental diagram (MFD) for an urban street network. The derivation of the IFD from basic definitions, together with some mathematical consequences, is described. As a result, rather simple formulas are given which allow the determination of traffic performance parameters from the results of simple traffic counting. Thus, the IFD provides a method to estimate measures of effectiveness for an intersection, such as average velocity or average loss time, based on automatic counting equipment. The derivations start with rather simplified assumptions, which then are extended to account for more complex situations. An example, applied to a roundabout, demonstrates how an IFD can be formed based on real-world data. For more comprehensive evaluations, the roundabout has been modeled by microsimulation. Thus, IFDs can be presented based on a wider sample size for varying external conditions. The results demonstrate several influencing factors for the shape of a roundabout-IFD. Here, for example, the effect of pedestrians who cross the entries and exits of the roundabout, can be demonstrated. These initial studies underline that the IFD can become a tool to assess the performance of an intersection based on simple data acquisition techniques. It can be expected that, because of further improved automated counting techniques, also based on floating cars, this approach may play a more important role in the future.

Roundabouts provide a significant potential to improve traffic safety. The paper contributes an overview about research results on safety at roundabouts with a focus on urban intersections. Even if it is written from a German perspective, it includes results from several other countries. As a conclusion from all studies, there is no doubt that roundabouts are the safest type of intersection. Especially the single-lane roundabouts reveal the highest level of safety. Also mini-roundabouts have an extraordinary good safety record. Turbo-roundabouts—regarding safety—are on the same level as the single-laned. This high degree of traffic safety is strictly depending on the speed-reducing design of the whole intersection. In comparison to conventional types of intersections like signalized or two-way-stop intersections, the car occupants and the pedestrians enjoy the highest gains from roundabout safety. On the other hand, bicyclists can become a problem for traffic safety at roundabouts. However, also cyclists can be operated with a sufficient degree of safety—but only if the requirements for design are strictly obeyed. It should be emphasized that the high degree of safety is coherent to road user discipline and to the acceptance of the existing traffic rules. This acceptance should be strengthened by an adequate intersection design. Therefore, the favourable safety effects of roundabouts can only be achieved if the rules for modern roundabout design, as they are documented in many national design guidelines, are strictly applied.

The estimation of capacities and traffic performance at two-way-stop-controlled (TWSC) intersections has been the subject of investigations conducted by many researchers. The results of these investigations are incorporated in highway capacity manuals like the U.S. Highway Capacity Manual (HCM) or the German Handbuch für die Bemessung von Strassen (HBS). Although the underlying methodologies are similar, there are two major differences between the current HBS 2015 and HCM6: (a) the procedure for the impedance factor for movements of rank 4 and (b) the procedure for estimating the capacity of shared short lanes for both minor and major movements. In HBS 2015, new developments are accounted for and the accuracy of capacity and traffic quality estimations significantly improved. In HCM6, these two procedures have not been updated. Therefore, the replacement of the two procedures in HCM6 is recommended. In both HCM6 and HBS 2015, the procedures for calculating delays at shared lanes or shared short lanes are inaccurate and they also should be updated. In most cases, the delays are significantly underestimated. Recently, the authors have developed a new methodology dealing with this problem which can be easily incorporated into future versions of HBS and HCM. In this paper, the theoretical backgrounds of the three new methods are presented and major results are summarized. Compared with HCM6, the advantages of the new developments are highlighted. As a recommendation, three corresponding procedures for estimation of capacity and delay are given for potential use in a future version of HCM.

Estimation of the capacity of mini-roundabouts is under discussion. Existing methods treat mini-roundabouts as analogous to larger roundabouts, assuming independence between operation of the entries. They fail to acknowledge the specific way that traffic operates at these narrow intersections. This study proposed a new model, which aimed to accommodate the peculiarities of mini-roundabouts: priority for upstream entry, capacity increasing effects of exiting vehicles, and heavy vehicle operation. The model resulted in a set of equations that can be solved iteratively. It was applied to a set of examples in which the model parameters were estimated according to existing guidelines. Test calculations showed: compared to the current German guidelines the model leads to a reduced total intersection capacity. Further calibration and tests for practicability are recommended.

At unsignalized intersections, both on the major street and on the minor street, there may be short turning lanes alongside the through lanes following downstream from one single lane. This combined system is termed a shared-short lane (SSL). Up to now it has only been possible to calculate the capacity of these lanes at the stop line and the capacity of the diverging point, where the turning lane diverges from the through lane. For the total average delay of the involved individual movements, there is no applicable estimation procedure. As a special case, the shared lane (SL), which is used by several movements without a separate turning lane, must also be reconsidered. This paper presents a new model for the estimation of average delays of SSL with SL as a special case at unsignalized intersections. The model is based on the analogy to standard queuing systems. The results depend on the length of the short lane. The model is validated by simulation. The results demonstrate that the outcome of the models in current highway capacity manuals may be misleading, with the risk of inaccurately classifying the level of service of an intersection. Therefore, there is an urgent need to complete the relevant procedures in highway capacity manuals by more realistic estimation procedures for the total delay at an SSL or an SL. The methods in this paper-even if they are rather complex-are recommended to be incorporated into future versions of highway capacity manuals using some simplifications.

The conventional method of analysis for capacity of roundabouts is based on gap-acceptance methods or on empirical regression or a combination of both. The influence of pedestrians is modeled by reduction factors with a questionable empirical background. Thus, the current methods are based on an incoherent mix of approaches. Moreover, they do not account for the interaction between the different elements. The paper presents a new model which treats the whole intersection as one entity. Here all the conflict points where different streams (vehicles and non-motorized road users) intersect within the roundabout are identified. Each conflict point is treated as one queuing system with a simplified queuing mechanism. In addition, the interactions between the consecutive queuing systems are taken into account according to the theory of chains of queues where the distance (= storage area) between the conflict points becomes important. The paper explains the development of the model, presents the mathematical derivations of ready-to-use capacity equations plus parameter calibration by existing data, and demonstrates its real-world application. The advantage of the technique is that all conflicts-both between vehicle streams and with pedestrians at entries and exits-are treated by the same congruent methods. In addition, the interactions between consecutive arms of the roundabout are modeled. The method can also model limited priority (e.g., for pedestrians at crosswalks) for all conflict points. Finally, the conflicts that are decisive for the performance of the whole intersection are identified. The method can be easily implemented into computer software.

For the estimation of critical gaps for unsignalized intersection analysis, the so-called maximum likelihood method currently is treated as the best approach. This paper demonstrates that the maximum likelihood method is a special case of the more general mathematical survival theory for the estimation of interval-censored parameters. The assumption of a special mathematical type for the statistical distribution of critical gaps is an essential part of the method. Test applications with various types of functions show that the results do not significantly depend on the applied type of distribution. Therefore, the traditional lognormal distribution is not an essential part of the theory. Instead, it is reasonable to apply that type of distribution that can be handled more easily. From this standpoint, the logistic distribution is favorable. Because the variance of each kind of distribution of the critical gaps does not contribute to the precision of the result, a simplified method is useful if the standard deviation of the critical gaps can be predefined and if only the scale parameter of the function is adjusted to the measured gap data. The results from this single-parameter method are rather congruent with those from the more complicated two-parameter method. The simplified approach opens the way to apply critical gap estimation in traffic engineering practice to adjust capacity calculations to local driver behavior.

For unsignalized intersections, the average delay suffered by drivers on minor approaches is treated as the parameter to characterize the quality of service. The current method, as it is used by guidelines around the world, has some shortcomings. It neglects the initial queue at the beginning of the interval for observation, and it cannot account for realistic conditions during the subsequent interval. Both aspects make existing delay equations useless to analyze a sequence of time intervals. A new delay equation for unsignalized intersections has been derived; it can include the effects of an initial queue and of variable capacities. With these characteristics, it can be applied if a longer series of time intervals (e.g., 1 day) is analyzed. As with all current approaches, the new equation is also an approximate solution. It was tested by exact numerical calculations and by simulations. By these comparisons, the new equation demonstrated quite a high performance.

In Deutschland haben sich vor allem die kompakten einstreifigen Kreisverkehre bewaehrt. Das Bestreben vieler Planer war und ist es, jenseits von deren Leistungsvermoegen auch groessere Verkehrsnachfragen durch einen Kreisverkehr abzuwickeln. So sind die sogenannten zweistreifig befahrbaren Kreisverkehre entstanden, die seit 2006 in einem Merkblatt der Forschungsgesellschaft fuer Strassen- und Verkehrswesen (FGSV) beschrieben sind. Durch eine neuere Untersuchung sind diese Kreisverkehre hinsichtlich ihrer Sicherheit und ihrer Kapazitaet untersucht worden. Dabei kann das hohe Sicherheitsniveau bekraeftigt werden, das auf einem vergleichbaren Niveau wie die einstreifigen Kreisverkehre liegt. Auch die grundsaetzlichen Angaben zur Kapazitaet aus dem Merkblatt (2006) werden bestaetigt. Wesentlich ist aber, dass zweistreifige Einfahrten zu dreiarmigen Kreisen eine hoehere Kapazitaet aufweisen. Es bestehen auch Moeglichkeiten, die Kapazitaetsreserve oder die Laenge des zweiten Fahrstreifens genauer in die Berechnungen einzubeziehen. Die Information, dass mit laengerer Dauer der Ueberlastung die Kapazitaet steigt, laesst sich nur schwer in ein Bemessungsverfahren einbauen. Insgesamt ergibt sich eine massvolle Anpassung frueherer Kapazitaetsangaben. Der Artikel wird fortgesetzt mit einem Aufsatz ueber Turbo-Kreisverkehre. (A) ABSTRACT IN ENGLISH: In Germany compact single-lane roundabouts have proven to be rather useful solutions for intersection design. Many planners, however, like to manage larger traffic demands by roundabouts than the single-lane solutions can afford. Thus, the so-called semi-two-lane roundabouts have been developed as they are described in an FGSV guideline from 2006. This means that cars are able to operate side by side whereas larger vehicles need the full width of the circle to drive through the intersection. By more recent investigations both the capacity and the safety had to be checked in comparison to the guideline. As a result the high level of safety as it is comparable to single-lane roundabouts can be confirmed. Also regarding capacity the former information, in principle, is still valid. However, as a new insight the capacity of two-lane entries at three-arm roundabouts is significantly larger than expected. Due to the orientation of traffic according to directions the left lane is more intensively accepted. Another result was that with longer duration of oversaturation the capacity is increasing. Overall, only a moderate modification of capacity assumptions is required. The article will be continued by a paper on turbo-roundabouts in the next issue of the journal. (A)

Ramp-metering, which controls the onramp flow into the freeway, is successful in increasing freeway throughput and reducing overall travel-time. The maximum flow allowed from the onramp during ramp-metering is typically estimated so that the sum of flows from the onramp and mainline do not exceed a predetermined threshold (either the capacity of the downstream section or a threshold based on occupancy at capacity). Recent research has shown that this threshold is probabilistic and the transition from noncongested to congested conditions (i.e.,breakdown) occurs stochastically. Also, research has shown that the contribution of the ramp and freeway demands on breakdown is different; 100 additional vehicles arriving from the ramp increase the probability of breakdown more than 100 additional vehicles from the freeway. This fluctuation has been studied through the development of breakdown probability models, which provide the probability of breakdown as a function of the combination of the mainline and ramp flows. The writers' objective was to develop suitable site-specific probability of breakdown models and use them within existing ramp-metering algorithms to evaluate their ability to postpone the breakdown and reduce congestion at freeway facilities with recurring congestion. The writers first develop a process for obtaining breakdown-probability models for existing critical ramps (i.e.,those where breakdown starts). Next, the writers propose specific enhancements to existing ramp-metering algorithms that incorporate probability-of-breakdown models. Proposed enhancements are presented for two algorithms, as follows: (1)the Minnesota stratified ramp-metering algorithm (SZM), and (2)the Ontario COMPASS algorithm. Simulation was used to replicate these algorithms and evaluate the proposed enhancements. The results of these experiments showed that the enhancements are effective in postponing congestion at the two sites by 17-35min.

Die Forschungsarbeit behandelt die Vor- und Nachteile der Teilung einer vierstreifigen Richtungsfahrbahn einer Autobahn in eine Hauptfahrbahn ohne Anschlussstellen fuer den Fernverkehr und eine getrennte Fahrbahn fuer den lokalen Verkehr hinsichtlich des Verkehrsablaufs. Diese getrennte Fahrbahn erschliesst die Anschlussstellen ins nachgeordnete Netz und verfuegt nur am Anfang und Ende ueber eine Verbindung zur durchgehenden Hauptfahrbahn. Waehrend eine solche Verkehrsfuehrung in den Ballungsraeumen im Ausland erfolgreich Verwendung findet, ist sie in Deutschland bisher weitestgehend unbekannt. Im Rahmen der Forschungsarbeit wurden lange Verteilerfahrbahnen an Autobahnen zur raeumlichen Trennung von durchfahrendem und ausfahrendem Verkehr hinsichtlich ihres Verkehrsablaufs untersucht. Anhand einer umfangreichen empirischen Untersuchung und darauf aufbauenden mikroskopischen und makroskopischen Simulationen sollten insbesondere Einsatzkriterien fuer lange Verteilerfahrbahnen festgelegt werden. Ziel der Untersuchung ist es, anhand der gewonnenen Erkenntnisse aus Gruenden des Verkehrsablaufs Entscheidungsgrundlagen fuer die Trennung von Fernverkehr und oertlichem Verkehr mit langen Verteilerfahrbahnen bereitzustellen. (A) ABSTRACT IN ENGLISH: In many densely populated urban areas distributor lanes become installed to separate the traffic on motorways into local traffic on distributor lanes and long-distance traffic on express lanes. While distributor lanes and express lanes are common in foreign metropolitan areas, this solution is nearly unknown in Germany. The research project investigates the potential of distributor lanes for use in Germany. In a first step the traffic flow of German collector roads was analyzed by empirical methods. Based on these results and on extensive microscopic and macroscopic simulations, criteria and deployment guidelines for the use of distributor roadways were defined. The study provides warrants to decide on the separation of long-distance and local traffic on motorways. (A)

The term breakdown of flow at a freeway bottleneck location has been used to describe the transition from relatively free-flowing traffic to congestion, often called stop-and-go traffic, but more generally experienced as slow-and-go. The focus of the research presented in this paper was to develop probabilistic models to predict breakdown of flow by using data from five freeway-ramp merging segments. The development of the probabilistic models allows exploration of several issues: the identification of breakdown, the performance measures for the identification of the breakdown, and the breakdown location. The breakdown probability model (BPM) is based on lifetime data analysis statistics. The breakdown probability models can be very useful tools in establishing capacity values, which in turn can be part of the freeway traffic management process. (C) 2013 American Society of Civil Engineers.

Germany has a long tradition of traffic-actuated and -coordinated signal control. In recent years a specific approach to traffic actuation called a model-based system, or adaptive control, has found its way into practice. In the city of Muenster, Germany, the coordinated signal control system on the 6-km-long arterial Albersloher Weg, with 24 signalized intersections, has been completely renewed in a three-step process involving the old system, a rule-based traffic-actuation system, and an adaptive system. An empirical evaluation of this process by a university research team showed that conventional actuated signal control improved traffic performance in the first step. Additional significant improvement (as much as 30%) in traffic flow performance could be achieved by implementing Motion, an adaptive signal control system. However, further developments are required to meet the expectations of city engineers and road users. In particular, switching between optimized signal plans, which is an essential feature of the Motion system, must be improved.

Ziel der Untersuchung war es, anhand realer Faelle adaptive Steuerungen von Lichtsignalanlagen fuer staedtische Hauptverkehrsstrassen mit konventionellen Steuerungen zu vergleichen. Fuer die Untersuchung wurden je zwei Hauptverkehrsstrassen in Muenster und Remscheid ausgesucht, auf denen adaptive Steuerungen eingerichtet wurden. Dabei wurde zunaechst eine konventionelle Koordinierung mit weitgehend verkehrsabhaengigen Elementen hergestellt. Zusaetzlich konnte jeweils eine adaptive Steuerung geschaltet werden. Auf allen Strecken wurden systematisch Testfahrten bei Schaltung der verschiedenen Steuerungszustaende durchgefuehrt. Die hierbei mittels GPS aufgezeichneten Fahrzeugtrajektorien wurden hinsichtlich der Anzahl von Halten und der Wartezeiten analysiert, um so zu einer verkehrstechnischen Beurteilung zu gelangen. Auf der ersten Teststrecke in Muenster konnte durch die adaptive Steuerung eine deutliche Verbesserung des Verkehrsablaufs erreicht werden. Auf der zweiten Teststrecke in Muenster liess sich dieser Erfolg nicht wiederholen. Es traten teilweise erhebliche verkehrliche Verschlechterungen bei Schaltung der adaptiven Steuerung ein. Auf den Teststrecken in Remscheid ergaben sich durch die adaptive Steuerung in jeweils einer Fahrtrichtung Verbesserungen des Verkehrsflusses. Dem stehen jedoch Verschlechterungen in der Gegenrichtung gegenueber. Weil eine direkte Erfassung der Immissionen vor Ort nicht moeglich war, wurde eine Antwort hinsichtlich der oekologischen Wirkungen durch mikroskopische Simulation gesucht. Fuer je eine Strecke in Muenster und Remscheid wurde die adaptive Steuerung in ein VISSIM-Modell integriert. Die simulierten Fahrzeugtrajektorien wurden durch das Verfahren PHEM im Hinblick auf die Schaetzung der Emissionen analysiert. Dabei zeigte sich in Muenster eine leichte Verbesserung (1,0 %) der oekologischen Auswirkungen als Folge der adaptiven Steuerung. In Remscheid zeigte sich nach den eingetretenen unguenstigen verkehrlichen Wirkungen erwartungsgemaess auch eine Verschlechterung der oekologischen Auswirkungen. Die Ergebnisse der mikroskopischen Simulation in Verbindung mit der adaptiven Steuerung auf diesem Streckenzug unterlagen jedoch erheblichen Schwankungen, sodass hiermit lediglich tendenzielle Aussagen moeglich sind. Im Ergebnis zeigte sich, dass die adaptiven Verfahren die Moeglichkeit eroeffnen, den Verkehrsfluss auf staedtischen Hauptverkehrsstrassen zu verfluessigen. Dabei koennen auch Verbesserungen hinsichtlich der Schadstoffemissionen und des Energieverbrauchs eintreten. Diese Verbesserungen koennen jedoch nicht uneingeschraenkt vorausgesetzt werden, sondern beduerfen einer zum Teil laengerfristigen, kostenintensiven Einstellungsphase. ABSTRACT IN ENGLISH: The research aimed at a comparison of signal coordination with adaptive traffic control systems (ATCS) and conventional traffic-actuated signal control systems in existing urban areas. ATCS performance was analysed on four selected urban arterials in Muenster and Remscheid. On these corridors a conventional traffic-actuated coordination was installed that could be switched over to ATCS. Data collection on all corridors was conducted to gather empirical data for the different signal control systems. The vehicle trajectories were analysed considering the number of stops and the delay. ATCS implementation in Muenster on the first corridor improved traffic flow significantly while on the second corridor diverse results were gained together with partly significant declines in the level of service with the ATCS. The traffic flow quality on the corridors in Remscheid could be partially improved by the implementation of ATCS, but declines were also identified. Due to the impossibility to measure immissions locally, the environmental impacts had to be estimated using microscopic simulation. For one corridor in Muenster and one in Remscheid, the ATCS was integrated into the microsimulation program VISSIM. The simulated vehicle trajectories were analysed by the program PHEM to estimate the emissions. In Muenster, marginal improvements of 1.0% concerning the environmental impact were observed after ATCS implementation. In addition to the poor traffic-related effects in Remscheid, the ecological impact deteriorated as expected. The results of microscopic simulation in addition with an ATCS were afflicted with considerable erratic fluctuations implying that the results are only able to represent a tendency. As a result, ATCSs provide the possibility to improve traffic flow on urban arterial highways in addition to possible improvements of emissions and energy consumption. However, these effects usually cannot be taken for granted. In many cases a cost and time-intensive calibration process is required.

Die nationalen und internationalen Erfahrungen mit dem Verkehrsablauf auf langen Verteilerfahrbahnen an Autobahnen mit dichter Knotenpunktfolge wurden in einer Literaturrecherche und in Expertengespraechen untersucht. Neben dem Verkehrsablauf wurden ebenfalls Aspekte, wie die Wegweisung oder die erschwerte Erreichbarkeit fuer Rettungsfahrzeuge betrachtet. Basierend auf der empirischen Untersuchung von Dauerzaehlstellendaten konnte die im (Handbuch fuer die Bemessung von Strassenverkehrsanlagen (HBS) gegebene Kapazitaetsgrenze fuer einstreifige Verteilerfahrbahnen bestaetigt werden. In den mikroskopischen Simulationen von vier unterschiedlichen Autobahnabschnitten wurden die Auswirkungen des Einsatzes einer langen Verteilerfahrbahn untersucht. Neben einer starken Abhaengigkeit der Fahrtzeiten von den zulaessigen Hoechstgeschwindigkeiten wurde fuer den durchfahrenden Fernverkehr auf der getrennten Hauptfahrbahn ein bis zu 60 prozentiger Rueckgang der Fahrstreifenwechsel ermittelt. Dies fuehrt nicht nur zu einem harmonischeren Verkehrsablauf, sondern bewirkt ebenfalls einen spuerbaren Komfort- und Sicherheitsgewinn in der getrennten Verkehrsfuehrung. Basierend auf einer mit der makroskopischen Simulation durchgefuehrten Ganzjahresanalyse wurden in der getrennten Verkehrsfuehrung, je nach zulaessiger Hoechstgeschwindigkeit, eine Reduzierung der Fahrtzeit und der resultierenden volkswirtschaftlichen Zeitkosten ermittelt. Zusammenfassend laesst sich feststellen, dass bei stark schwankenden Verkehrsstaerkeanteilen die breite gemeinsame Fahrbahn aufgrund des Kapazitaetsausgleichs zwischen Fern- und Ortsverkehr sinnvoller ist. (A) (Beitrag zu Strassenentwurf und Verkehrsmanagement - Die Einheit von Planung, Bau und Betrieb von Strassen: Tagung, 17./18. November 2011, Dresden.)