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Routing server

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When using the Waze application, Waze servers use routing algorithms to determine the best path for a given route at that particular time. The specific details of the routing algorithms used by the Waze server are not publicly disclosed; the following is based on observation, speculation, and some information revealed by Waze staff. The operation of the routing server is considered to be proprietary and a competitive advantage to Waze. The information on this page is subject to change, and any information that has been revealed may be incomplete or out of date.
==Cálculo de una rutaClient-based routing ==Calculating an optimal route is a difficult task. While the client device app has a routing algorithm included, this is not used unless there is no connection to the Waze server. Client-based routing only uses cached map tiles. It does not use real-time traffic data, reports or closures, because this information is not accessible. Therefore, it does not provide an ETA.
== Routing requests ==
When a user requests a route calculation with a network connection, the request is sent to the Waze server. That route is then transmitted back to the client device and displayed.
Cálcular una ruta óptima es una tarea difícilThe requests for routing vary according to the settings chosen for the user's account on the client device. Si bien la aplicación en el dispositivo Under Navigation one can choose:* Whether to allow or avoid [[toll roads]]* Which, if any, [[Carpool, HOV, Transit lanes|toll and HOV]] passes to apply (clientesome segments are permitted only to those who hold the proper pass) incluye un algoritmo de enrutamiento que sólo se activa si hay una conexión con el servidor de Waze* Whether to avoid {{Ferry|Ferries}}* Whether to avoid {{Freeway|Freeways}}* Whether to allow, never allow, or avoid long unpaved roads* Whether to avoid [[Difficult turn|difficult intersections]] (turns marked "difficult" through nodes or junction boxes).* Vehicle type** {{Passageway}} has a type-specific [[Routing penalty|penalty]].** [[Partial restrictions|Segment restrictions]] allow or prevent travel by certain vehicle types.
== Especulaciones Different route lengths ==
=== Pruning ===
It is known that the Waze routing engine can't calculate every possible route for long-distance routes, so it takes shortcuts by removing lower road types from consideration in the middle of longer routes. This effect is commonly called '''route pruning''' and can potentially result in the route changing dramatically when lengthened slightly. At distances farther than a certain threshold value from the origin or destination of a route, roads lower than a certain type tend not to be considered. Pruning thresholds with confidential, variable, increasing values exist for {{Street}}, {{Primary Street}} and {{Minor Highway}}, respectively. There is evidence that {{Major Highway}} is never pruned. {{Freeway}} and {{Ramp}} are never pruned. The pruning mechanism uniquely accounts for [[Creating and editing road segments#Special properties|routing road type]], so a Primary Street with routing road type +1 would be pruned at the same threshold as a Minor Highway.
El algoritmo de enrutamiento que utiliza el servidor de === XL routes ===Generation of routes longer than 1000 miles in Waze no es de conocimiento para el público por lo que lo descrito a continuaciónused to be impossible, se basa en but in 2018 a en la observaciónnew mechanism for extra-long (XL) routes was put into place. This pieces together multiple long routes to generate one extra-long route. To save time and avoid routing timeouts, la especulacióninstructions and geometry details are omitted in the middle of the route during initial calculation, y alguna información revelada por el personal de Wazebut they are produced and listed later as the user drives along the route. Podemos suponer que el funcionamiento del servidor de enrutamiento es la estrategia de Dependent upon multiple factors such as server load and road types, transcontinental routes can be calculated in Waze para competir frente otros navegadoreswith this mechanism. También podemos suponer que está sujeto a cambiosIt is also evident that, since XL routes are combinations of shorter routes, the aforementioned pruning behaves differently for them, y que cualquier información que revelada puede ser incompleta o fuera de fechaso that lower road types may appear in the middle of extra-long routes.
==Solicitud de ruta de navegación Real-time current road speeds ==The routing server uses real-time road speeds (from recent Waze app users if available) and combines the average, historical speed of the segment broken down into 10-15 minute chunks. The time to pass through a segment is tracked separately for each route out of a segment. For example if a segment ends with only a left and right turn, then the routing engine isolates the time through the segment to turn left and the time through the segment to turn right. This detailed speed information is proprietary and is not displayed in the Waze Map Editor.
Cuando se solicita un cálculo de la ruta, ésta se envía al servidor de It is known that Wazeprefers to use real-time reports of current road speeds over historical average road speeds. Esa ruta se transmite de nuevo Waze also uses traffic congestion reports to reroute around slow traffic. <!-- Early versions of the client would also report when traffic speeds were good - this was removed due to map clutter. But Waze will still be receiving this information. -->The speeds of recent Wazers traveling on a su [[dispositivo cliente]] y se muestraroad will be factored into the route given to subsequent Wazers traveling on the same road.
Las rutas mostradas van As the number and density of Wazers grows, this real-time data takes on a variar en función de las opciones de configuración seleccionadas en el dispositivo [cliente]greater importance. En virtud de enrutamiento puede elegir:* La ruta más rápida o más corta* Permitir o no, el acceso This emphasis is partly a reflection of Waze's original goal to create optimal commutes. As Waze has grown to be used as a través de caminos de tierramore general-purpose GPS navigation device over roads less traveled, * Utilizar el menor número de giros * Evitar las autopistas (peajes ?)* O seleccionar rutas para ir comiendo galletas (da mas puntos)the historical average road speeds becomes more important.
La ruta más corta se refiere Since Waze uses the future expected time of arrival onto a la distancia física. La mejor opción es seleccionar la ruta más rápidaroad segment in order to calculate the expected speed on that segment, it cannot use real-time data too far in the future. So longer trips (100 km de autopista es mejor que 90 km de caminos ruraleson the order of 30 minutes or more)will include future time slots where current traffic data is not available when initially calculated. As the trip progresses, any real-time traffic data that is available causes the client to recalculate the route and the ETA.
Las galletas (Cookie munchin)aparecen en caminos que no han sido recorridos== Average road speeds ==If the average or historical road speed is not correct, then the route may not be optimal. Cuando se activa esta opciónHowever, la ruta tserá menos directa para viajar por caminos sin confirmardeletion of segments to reset average road speed is not recommended. Waze uses the data from Wazers traveling through the segments to update the average speed, (y vas sumando puntos)and oftentimes an anomalous historical road speed is automatically corrected with further data collection. Normalmente, esto incrementa en 10 minutos el recorrido, lo xual s poco importante en recorridos largosIf Waze appears to disfavor the use of certain segments along a route, pero si en los cortos . (un viaje de 3 horas se convierte en 3 horas y 10 minutos. Pero 20 minutos en coche se convierte en 30 minutos en coche)a number of other reasons can cause such a situation.
==Missing roads and incorrect junction connections= Time-of-day variations ===Waze tries to find Consider a road that most Wazers drive at 5 PM when the average speed is 12 MPH. At 10 AM when the fastest route between you road is clear and your destinationthe average speed is 60 MPH, it is the best road to take. Obviously If Waze only has historical speed data from 5 PM, it can only route based on roads will assume that the speed of the road is 12 MPH all day, and it knows aboutmay not recommend this road. As more people drive this road closer to the time of day when a given route is requested, so your route Waze will not be optimal if get a better route does not have all guess for the roads with correct connections in the [[Live Map]]== Carreteras "perdidas" y uniones incorrectas ==Waze trata de encontrar la ruta más rápida a tu destinoaverage speed at that time. Obviamente, pero escogerá una ruta alternativa , si la ruta óptima no tiene las carreteras con todas las conexiones correctas en el Mapa en Vivo [[Live Mapa]]
==Real-time current road speeds= Shrinking window ===We can be confident that If there are enough recorded speeds on a road, then Waze uses real-a shrinking window of speeds to better estimate the average speed at the current time reports . Waze uses the speed of current each road segment (in both directions) in intervals as small as 30 minutes. So a two-way road speeds by preference over historical might have up to 96 average road speedsin a day. We know It can be assumed that Waze uses traffic congestion reports when there are insufficient records for an individual time slot, a wider time range is used (up to reroute around slow traffica full day). Early versions of As the road is driven more at different times, the client would also report when traffic speeds were good - this was removed due to map cluttertime slot shrinks. But Waze will still be receiving this Additional informationis used based on the day of the week. We can assume There is no evidence that the speed of any wazer ahead of you on a stretch of road Waze records speeds for larger date ranges such as months or seasons; however, it will be the speed used update its average speeds relatively quickly when your route is calculatedseasonal traffic patterns change.
As Waze uses the average road segment speed for the number and density time slot that applies at the time when a user is expected to arrive at that road segment. Because of wazers grows this real-time data takes on a greater importancewindow, Waze suggests different routes at different times of day. This emphasis is partly a reflection dependent on how many times are recorded on the roads along the route. If they're all recorded at about the same time of Waze's original goal to optimise commutesday, then the time window does not help. As Waze has grown to be used as a more general purpose GPS navigation device over roads less travelledIf 1,000 times are recorded at about 5 PM and 2 times are recorded at 10 AM, then the historical 10 AM average road speeds becomes more importantspeed still is based mostly on times from around 5 PM.
Since Waze uses the time you expect to be at === Turn delays ===On a road segment to calculate the expected speed on that segment, it cannot use real time data when you trip time moves into a future time slot. So trips of more than 30 minutes (and on average more than 15 minutes) will include future time slots where current traffic data is not available. When you enter a new time slotroad, real-time traffic data may be available which may cause your client to recalculate your ETA and reroute you.==Fastest routing==Waze knows the a user's average speed of every confirmed road between you and your destination. The Waze server can calculate which list be very different depending on what is done at the end of roads to take to minimize the total travel segment. Traffic going straight through a traffic light might go very fast while traffic turning left might wait a very long time. A freeway exit lane might go fast while traffic continuing hits congestion.
While every request is processed in real-time, by observation it appears that Waze [[glossaryImage:SegmentTraffic1.png|right|caches350px]] some requested routes or major points. This means if it already knows Waze has the best route from B ability to Cseparately track the average speed of traffic that passes through a segment, and you ask for a route from A but exits to Cdifferent segments. The routing engine takes this into account. In the diagram, it may just calculate multiple times are tracked for traffic flowing through Seg4 based on the best route from A segments to B, once which it checks that there isn't a better route bypassing B altogetherexits. This does mean that when there is a [[Timeline of updating process|Live map update]] some routes may be less than optimal There are then two average drive times for up to a day as routes are cached and recalculated.:
While a complex calculation, calculating the optimal route is possible. The complexity arises over the "average speed" of the roads.* Seg4 to Jnct2 to Seg5
==Changes in route due * Seg4 to different [[glossary|origin]]==Consider calculating a route from A Jnct2 to Z. The suggested route may be A to B to C to D to Z. Then calculate the route from B to Z. You may get a suggested route of B to C to E to Z. At first glance, this suggests one route is not optimal.Seg6
We can guess at what might be happening. There may be a problem associated with Traffic building up on Seg4 that turns right to Seg6 does not affect the possible caching of routes. Or there may be a "route timing window" effect. The different arrival time at C may change for the best route traffic also using Seg4, but instead turning left to ZSeg5. Or there may be a fine tuning effect in the route, perhaps For this reason it is important to avoid too many turns. So by dropping the keep long segment A to B, lengths before junctions as traffic congestion at the segments C to E to Z no longer exceed some thresholdjunction might affect exits differently.
This effect To understand this problem better, consider if we add a short Seg8 between Seg7 and Jnct4. Let's say the traffic exiting Seg10 backs up all the way to Seg7 (easy enough, since Seg8 is short). Because Seg7 only has a single exiting segment (Seg8), the routing server is only able to collect a single average speed &mdash; it can be observing while drivingno longer distinguish traffic by where it is going ''after'' Seg8. If you recalculate a route Now the through traffic going to Seg9 appears to Waze to slow down through Seg7, even though it doesn't in reality. At a destination while driving along minimum this causes an already calculated incorrect ETA for routing, and it might actually cause traffic to be rerouted unnecessarily, and less optimally, through another route to . Hence, if there is a chance that traffic can go in different directions at a junction and that same destinationjunction can experience different amounts of congestion, the route segment before the junction should be kept long, or a [[junction box]] may changebe used.
=== Outdated and abnormal road speeds ===Average speeds can change over time, and recorded times can be abnormal or wrong—and can stay wrong for a very long time. This may be due to users recording inaccurate speed data by doing things like walking, biking or sitting in their driveways with Waze open. Also, if [[Segment length|segments are old reports where wazers have less than {{:Segment length/Minimum}}]] they may not offered a route be long enough to bypass heavy traffic but do receive a new route when manually asking for itrecord accurate transition times. It may be they would have been offered There is some evidence that alternative route at that point anywayabnormal road speeds and old road speeds are discarded, whether or at least not there was bad traffic ahead. It does raise question as to when and how Waze considers rerouting but these may have been addressed used in calculating the current version. Certainly Waze does offer new routes sometimesaverage speeds of roads.
==Changes in routes due to different route lengthsRecalculation ==When Waze receives notification of traffic conditions, it uses the actual speed of roads on your route, rather than the average speed. This is based on [[Real time closures|real-time closures]] and automatic traffic condition reports - light, moderate, heavy traffic or complete standstill. Manual reports of traffic jams and accidents are for display only and do not change routing.
In addition, it ETA is known that the Waze routing engine can't calculate every possible route for long distance routes, so takes shortcuts for longer routes, potentially resulting updated in the route changing dramatically when lengthened slightly. According response to Waze support (as of July 2011), a user's progress on the section of a route more than 10 km from each endpoint is heavily weighted towards non-streets (i.e. "Primary Streets" or the various Highway types). My personal guess is that it simply ignores streets outside of the 10 km radius from the endpoints when doing its calculations to speed up the calculation. The specific quote from support was: "Above some distance (currently 10KM) from both end points (start and destination) the server prefers in response to go through non streetsthese real-time traffic conditions. Now as it happens here If real- this small distance was time traffic conditions make the difference between being less given route significantly worse than or over 10KMalternatives, Waze may provide an automatic recalculation. Now the penalty The benefits of going through a street in this case is high - so are balanced against the server prefers the highway." In this particular case, the observed behavior was that extending the route by a short distance caused Waze to suggest a very different (and much longer, both in distance and estimated time) perceived hassle of changing one's route.
==Problems with average road speeds==If the average road speed is not correct, then the route will not be optimal. The following are reasons why using the average road speed can be the wrong value to use.===Time of day variations===Consider a road that most wazers drive at 5pm when the average speed is 12 mph. You choose your route at 10am when the road is clear and the average speed is 60mph. It is the best road to take, but Waze chooses a different route because it has no information about the speed at 10am and assumes the speeds is 12mph all day. You can, of course, drive the road yourself, and Waze will eventually learn. We do not know how many times Waze uses in its calculation. However if Waze does discard old time information, you may not accumulate new time faster than it is discarded. It is also possible that your times are being ignored as being abnormal. More Waze users would help fix this. ===Turn delays===Consider a road of length 1 mile where you drive straight ahead and go through the intersection all at 100mph taking 36 seconds. Or at the end of the road you can sit and wait 5 minutes to make a turn. In the first case your average speed is 100mph. In the second case your average speed is just under 11mph. Now if 9/10 wazers go straight through, the average road speed is 91 mph. Waze will recommend this route, even if if involves a turn on your route, and the route is not optimal. Contrariwise, if 9/10 wazers make that 5 minute turn, the average road speed is 20mph, and even though your optimal route would take you straight through at 100mph, Waze will not suggest it because it sees the average speed as 20 mph.  We can assume Waze is aware of this issue. You can choose the Minimize Turns option in your Routing settings. Or you can use your own discretion. The good news is that by collecting your route information Waze is collecting enough information to give correct routing advice when it implements it. It knows the average speed of people going straight through and it knows the average speed of people making the turn. And it can apply the correct average speed when calculating your best route. It make the calculation more complex, but it can be done. At the moment it is not being done. ===[[Cartouche]] editing===The average speed of a road can be dramatically altered by editing in Cartouche. Consider a 50m length of road driven in 36 seconds. An editor extends this length of road the full 10km length. Cartouche now records this road as 10km long but also driven in 36 seconds for an average road speed of 1000km/hour. This has been a particular problem as people adjust the length of ramps.==Traffic lights and stop signs==
Waze does not record the location of traffic lights. While some GPS navigation offers guidance like "turn right at the next traffic light" the information is frequently incomplete, incorrect or outdated. The consensus view is that Waze should not record the location of traffic lights.
Waze does take traffic lights and stop signs into account by noting the effect they have on traffic speed. Consider a traffic light with long waiting times. The road segment leading to that traffic light will have a low average speed. If the average speed (based on the average waiting time) becomes long low enough, a longer route that avoids the light will become becomes the preferred route. This has been observed in practice and is an example of ''emergent behaviourbehavior''. Waze isn't programmed to avoid traffic lights but it will does avoid slow roads; if the traffic lights make the road slow then Waze will avoid avoids them. Some drivers will regularly take longer routes—even winding through side streets—to avoid any stops or traffic lights. Waze has been known to suggest this, and also known to revert back to waiting at lights when better average speed information is collected from the side streets. But note that this can be less than optimal due to the turn delays discussed above. ==Outdated and abnormal road speeds==Road conditions change, construction work comes and goes, and average road speeds can change dramatically. One day you may be stuck behind a truck, and another day you may be crawling along the roads at 2 a.m. transporting your pet goldfish. Or your GPS might have a glitch and show you travelling at 1,000 mph. In short, average speeds can change over time, and recorded times can be abnormal or just plain wrong—and can stay wrong for a very long time. We can assume Waze is aware of this. There is some evidence that abnormal road speeds and old road speeds are discarded, or at least not used in calculating the average speeds of roads. ==Average road speed "shrinking window"==If there are enough recorded speeds on a road, then Waze uses a shrinking window of speeds to better estimate the average speed at the time you are travelling on it. Waze uses the speed of each road segment (in both directions) in intervals as small as 30 minutes. So a two-way road may have up to 48 average road speeds. We can assume that when there are insufficient records for an individual time slot, a wider time range is taken—up to a full day. As the road is driven more, the time slot would shrink down to 30 minutes. We can speculate that there may be additional information used that is based upon the day of the week. There is some observational evidence that a road that is busy on weekdays and not used for routing will be chosen as the optimal route on weekends. At some point, Waze would also need to consider the months of the year as seasonal variations can affect the speed of the roads. Waze uses the average road segment speed for the time slot that applies at the time you are expected to arrive at that road segment. Because of this "time window", Waze will suggest different routes at different times of day. This is dependent on how many times are recorded on the roads along the route. If they're all recorded at about the same time of day, then the time window will not help. If 1,000 times are recorded at about 5 p.m. and 2 times are recorded at 10 a.m., then your 10 a.m. average speed will still mostly be based on times from around 5 p.m. ==Routing algorithm refinements=====Routing options===It's easy to see how routing options can be implemented. For example, to minimise turns we can add a time penalty for fastest routing or a distance penalty for shortest routing, when calculating the fastest or shortest route.  ===Junction penalties===Currently Waze applies a five-second time penalty when calculating a route that passes through a junction. While not an unreasonable approach to dealing with intersections, it has generated some flawed routing and is being reviewed.  One major issue arises in long highways which may be made up of hundreds of segments connected together, as this may add a penalty of as much as five minutes to a trip, even though the intersections are not real. This supports the arguments of those who aim to have a clean edit of maps where junctions are only used when necessary. In practice, we need to deal with the map as it stands. An automated tool to remove the junctions is needed as the manual work that is required is enormous. The routing problem can be fixed in a variety of ways. One could:* Not apply the penalty when there are no other existing roads meeting at the junction;* Not apply the penalty when you cross a junction onto a road with the same name;* Not apply the penalty when the road you are travelling on is a higher class (e.g. highway versus street, primary street versus street), where we can assume the higher class road has the right of way; or* Not apply the penalty at all when travelling on freeways, motorways and highways. Even if a road is correctly connected with no unnecessary segments, the junction penalty can still give incorrect results. For example a busy highway may be correctly connected to the ramps along its length. A quiet country road running in parallel may not have all the minor connecting roads recorded; it looks like a straight section of road with no junctions. Waze may choose the country road as the preferred route because of the lack of junctions. ==What to do if you think the generated route is wrong==Firstly, use the option to generate alternative routes. This may give you some clues as to why Waze is offering that route. Secondly, if you think there is a better route, check in Cartouche that the roads are all connected along the route.
ThirdlySome drivers regularly take longer routes — even winding through side streets — to avoid any stops or traffic lights. Waze has been known to suggest this, post a message detailing the problem route - origin, destination and a Cartouche [[permalink]] also known to revert to waiting at lights when better average speed information is collected from the [http://wwwside streets.waze.com/forum/viewforum.php?f=6&sid=2872533f5796ac39dc6747511398e907 Navigation forum]. Other eyes will check it, and you may indeed find a flaw in But note that this can be less than optimal due to the Waze routing algorithm. Fixing it may make it better for everyoneturn delays discussed above.
==Change of RoutingWhat to do if you think the generated route is wrong ==When # Use the option to generate alternative routes. This might give you some clues as to why Waze receives notification of traffic conditions it uses is offering that route.# If you think there is a better route, check in the actual speed [[Waze Map Editor]] that all of its roads on your routeare connected, rather than and all legal turns are allowed.# Communicate the average speedproblem. This is based only Possible means of communication include:#* Report a [[map issue]] in the app and respond to comments on it.#* Post a message detailing the automatic traffic condition reports - lightproblem route (origin, moderate, heavy traffic destination and a WME permalink) to the [http://www.waze.com/forum/viewforum.php?f=6&sid=2872533f5796ac39dc6747511398e907 Navigation forum] or complete standstillyour state's local forum. Manual reports of traffic jams and accidents are for #* Join your local community's Waze Discord server (accessible from your information only and do not change routingstate wiki page). This will usually produce the fastest response from local editors.
It may be == You are the driver ==Waze can never see that even with the traffic reports, there light is green going straight or know that today is a public holiday. It can offer you guidance as to what is no better the best route under average conditions. But you are the driver and Waze will not offer you oneare in the best position to make the decision for today under today's conditions.
==You are the driver==If everyone followed Waze directions and never drove on a new route, Waze can might never see learn that the traffic light route is better. When Waze is green going straightrecording your travels, or every trip helps make Waze better for everyone. That includes when you think you know that today is a public holidaybetter. Sometimes you will be right. It can offer And sometimes you guidance as to what is the best route under average conditionswill be wrong. But it is better to find out you are wrong so you can choose the driver and better route. And when you are in right, all Waze users benefit by the best position to make the decision for today under today's conditionssharing of your knowledge.
If everyone followed [[Category:Waze directions and never drove on a new route, Waze may never learn that route is better. When Waze is recording your travels, every trip helps make Waze better for everyone. That includes when you think you know better. Sometimes you will be right. And sometimes you will be wrong. But it is better to find out you are wrong so you can choose the better route. And when you are right, all Waze users benefits by sharing in your knowledge.operations]]
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