PRE2016 4 Groep5

Group 5: AED Drone from TU Delft

• 1. Thom Konijnenberg 0945007 t.j.c.konijnenberg (At) student.tue.nl
• 2. Rense Nijenkamp 0960705 r.c.j.nijenkamp (At) student.tue.nl
• 3. Nikolay Stoyanov 0980910 n.stoyanov (At) student.tue.nl
• 4. Wessel van der Heijden 0951686 g.w.v.d.heijden (At) student.tue.nl
• 5. Patrick Shaw 0900654 Pthom.shaw (At) gmail.com

Introduction

Cardiac arrest is still a serious problem in the Netherlands. When it occurs, the survivability rate outside of the hospital is less than 10%. The reason for such a low survival rate is due to the fact that after a cardiac arrest, only an AED or a defrilibator can revive the heart and with every minute passing, the chance of surival drop with another 10%. However, the AED Drone from TU Delft is a solution as it can reach the patient faster than an person can who still has to retrieve an AED. However, the Drone from Delft is just a proto-type and has not been further investigated on issues like psychological and ethical connections to the TU Delft ambulance drone.

Problem statement

• Landing an ambulance drone as fast as possible in a crowded environment.

AED Map

Based on the AED map, made by the Red cross, one can pinpoint every location of an AED. However, one can conclude that there are certain area’s which are not covered by AEDs. From every AED, a circle is drawn with a radius of 500 meters. This is based on the distance one could access the situation, locate the nearest AED, retrieve it, and apply the AED to the patient. The 500 meters will take almost 10 minutes, giving the patient a chance of less than 10%. The biggest issue is still the time it takes to return with an AED. In order to get the survivability to reasonable numbers, the time must be made shorter. To get an response time within 3 minutes, which are called the golden minutes, is the main goal, as after 3 minutes brain damage will be caused. (link to Nikolay and picture of Alec mont). Therefore, help needs to arrive quickly in order to make a full recovery. The 500 meter are in reality little to 50 meter if one wants to apply the AED in the golden minutes.

Map Needs to be placed here:

For the current map, an area of 28 square kilometers has been taken, in which 60 AEDs are visible. These 60 cover about 50% of the area. Furthermore, of these 60 AEDs, about 40% are accessible at any given time, while the remainder is limited to the business hours of its location. Placing more AEDs in strategical places is an costly project. Most of the AEDs are over the price range of 1000 Euro and need an outside protector, otherwise it will be limited to the opening hours of its location. At the moment, an AED is placed when the owner feels the need to buy one or when it is a public building. This causes area’s which are used for homes and not for businesses or public buildings to be left without an AED. It can be seen on the map that those areas are usually more than 1 kilometer removed from the nearest AED. This will be almost certain death.

Because the time in which a cardiac arrest happens and the time a person calls the emergency number is already so costly on the patients live, a faster system must be used. The AED Drone has a response time of 1 minute inside its 2 kilometer radius. Because of this response time, the chances of survivability are greatly improved. At the moment, there is no better solution as the AED drone brings help at an unraveled speed, helping the patient in the golden minutes. This is caused by the speed of the drone and lack of traffic it finds on its path. Placing AED Drones around Eindhoven, will not only be the cheaper solution, compared to strategically placing AEDs everywhere, it will bring the needed equipment in the most critical minutes of the patients life.

Objectives

• How would the AED Drone improve the survival rate in Eindhoven.
• How does the crowd react to a drone landing from above.
• What protocol should people follow if the drone is in use.
• How should the drone behave to not disturb the crowd to a large extend.
• To what extend is the drone allowed to invade other people’s privacy in order to fulfill its objective.
• What are the factors when landing a drone.
• How can the landing speed of a drone be improved.

Users

Primary user

• People using the equipment delivered by the drone
• People who have the equipment used on

Secondary user

• Government
• Hospital
• Insurance
• Maintenance

USE

User

The users for the AED drone are different than users normally are, as the users from the AED drone are not prepared and is mostly forced upon them. When one comes across a collapsed person who has cardiac arrest, the user has to dail the emergency number and a drone will be send towards the location using the GPS of the person who called the emergency number. After a couple of minutes, when the AED Drone has arrived, further instructions will be provided, as is the norm with an AED. This is the main user for the AED drone, the one helping the patient. However, there are more users involved in this matter. Obviously, there is the patient himself. Even though the patient does not use the product, he has the most interest in the product being used well, since it's his life that is on the line. Another important user is the emergency services. Even though they do not really use the AED drone, the are helped by it a lot. If the patient is already being helped by the AED drone by the time the emergency services arrive, the patient has a much better survival chance. So indirectly, the AED drone has a lot of impact on the job of the emergency services. The final imporant user that we shall discuss is the insurance companies. Similarly to the emergency services, these companies are secondary users. They are interested in the wellbeing of the patient as well as the amount of money they need to pay to the patient or the patient's family.

Society

For society, this idea has a lot of impact. When a drone is used to help people survive a heart attack or other urgent healthcare problems, there are a number of issues which need to be dealt with:

• Privacy. Should the drone be able to access all locations? For example: entering someone’s garden in order to get to the victim. This is very important to the research because we are trying to save lives. However, this can't be achieved without thinking about the people. They need to specify what is acceptable for a drone. Taking a shortcut through another person's garden might increase the chances of survival for a patient, but the privacy of the bystander is at risk.
• Crowd control. What are the effects on a crowd of people when a drones passes by at high speeds? For example: a drone could cause a lot of panic within a crowd. Again, the same principle as before applies here. How far can the drone go in order to save lives? It should always be safe, but it should also handle a group of people with enough caution, but also have enough speed to get to its destination quickly.
• Parking. How can a parking space be created? How can you get a group of people to make room in an efficient way?

These three main issues focus on society’s opinions and behaviour. This needs to be analyzed by investigating completed studies on a variety of subjects regarding society’s view towards robotics used for healthcare. It is also important to look at the current rules that apply for emergency services such as the ambulance helicopter.

Enterprise

The main enterprises that will be impacted by this idea are:

• Insurance companies
• Hospitals and government
• Drone manufacturers

These enterprises have different interests when it comes to this idea. Whereas the hospitals, government and drone manufacturers might want there to be as many drones like this as possible, the insurance companies might not want this to happen. At the end of the day, the insurance companies main objective is to make profit. Having some expensive drones save lives might be more costly than deploying a “normal” ambulance, which will be more beneficial for the insurance companies. However, the survival of a patient might be worth a lot more than the costs of the drone. A person's life can't really be expressed in terms of money, so there are conflicting interests.

Issues

The ambulance drone is an unmanned aerial vehicle which means that it will need to use a camera in order for it to be operated. The drone will also move in crowded environments and will eventually interact with people. Therefore there are many issues concerning it’s behaviour. There should be rules concerning the ambulance drone, however there are currently no rules specifically for an unmanned ambulance drone, and therefore the drone will have to abide by the rules of consumer or business drones, which will currently prevent this project from taking off for real use. The good side is that there is a possibility that this project can be approved and have exceptional rules concerning it. However, for it to be approved, the drone must overcome dangers and ethical issues which will be discussed in the following sections.

Privacy

The camera itself brings a lot of issues concerning privacy. It is easy for a drone with a camera to gather different kinds of data. If a person is inputting his email on a computer, a drone can easily hover behind him unnoticed whilst recording it. Then it is needless to say that the person who has access to the video can without trouble learn the credentials of this email. Also people do not want to be seen what they are doing in their homes which can be unnoticably done by a drone. Drones can also be used for gathering economical data such as who are the people shopping on a given street . The drone’s purpose however is not to use the camera with such intentions and therefore some rules regarding the drones should be omitted and concern the ambulance drone. Even if such a drone may sometimes endanger invade the privacy of a person, that camera is needed for the drone to deliver life-saving functionality which is a reasonable trade-off.

Criminality

According to an article a man has shot down a drone which was flying over his yard. That same man has been sued by the owner of the drone and the judge ruled the man to be innocent. However during the case there has been discussion of the height at which the drone was flying. Which leads to the conclusion that if the drone has been flying high enough the man would not be legally allowed to shoot down the drone. The drone is supposed to fly high above the ground and at reasonable speed which means that people who try to shoot down or steal such a drone will not have done so with concern for their privacy, but with violent intentions and should be brought to justice for destroying/stealing government property.

Safety

There are also many issues concerning the safety of such a drone. This is why there are many rules to prohibit drones in many places. Many of these rules have been stated in the code of conduct for drones, however there are a couple of modifications that are needed for the AED. According to the law, a drone is not allowed to fly at night, this can be a huge problem, especially in the winter when there is not a lot of light. This would mean that the drones would only be allowed to work for a few hours, where an ambulance should always be available to help. Secondary, a drone should be seen when you're controlling it, this is a problem since these drones will be unmanned, should fly to areas where you can't be in time as a person. The drones are also not allowed to fly above buildings, roads and people, this would mean that drones aren't allowed in cities, where there are the most people that do potentially need help.

Liability

If AED drones were allowed to fly in cities, we get the following problem of who is responsible for the drones. since these drones are autonomous we have no direct control over where they fly, and thus there is always a possibility of the drone crashing into objects. There are many studies about autonomous robots and their liability [reference]. Currently we do not know who is responsible if such a drone crashes, which will be more clear if there are any regulations in place.

So even though there are a lot of problems when it comes to implementing the AED drone into society, an exception needs to be made. When it comes to saving lives, the law suddenly is not that important anymore. For example: an ambulance on the road is allowed to cross a red light at an intersection if it is in a hurry to get to a patient or a hospital. The same principle can apply to the AED drone. If all laws are taken into account, the AED drone simply would not be able to exist. It would be illegal, meaning the project is dead. Since this is a shame and we believe there is actually a future with the drone in it, we assume that the AED drone is allowed to break the law in cases of emergency. What's left to find out is how far the drone can go with this. The next step is to find out what a group of people think is acceptable behaviour for the AED drone in order to save lives.

Approach

• Literature research. Since we intend to add to an already existing product, we have to properly research what the already existing product is capable of doing. When these capabilities are determined, we can further develop the on our objective and the implementation into the already existing product. After this initial orientation stage, we go into the state of the art part of the literature research. This state of the art research focusses on literature connected to our objectives.

• Create a model of how the crowd environment reacts to a drone landing. When we have a majority of the state of the art research, we model the behaviour of the crowd into a model to see what kind of effect the drone has on the overall crowd. This focusses on the influence the drone has on its environment.

• The project is going to be focused on the User and Environment aspects. From those two aspects, the environment is going to play a major role as the crowded environment may act according to a pattern which we can analyze.

The Drone in use

The AED drone’s design has be narrowed down to 2 choices:

The AED drone will respond to phone calls regarding heart attacks nearby. It works as follows: A person (close to the person suffering from heart attack) calls the given number. He gets instructions on where the drone will arrive. Parallel to that an AED drone is dispatched to the calling peron’s location. The drone is supposed to autonomously travel at 200 km/h to the target location. However currently there is no collusion avoidance which works flawlessly at the target speed, so the drones may need to be operated manually until that technology is created. When the drone arrives it is picked up by the calling person who is supposed to bring it close to the person suffering from heart attack. The drone itself is equipped with a camera and microphone so the interaction between the operator and the people at the spot is achieved easily. After the drone is placed next to the patient, an able person is supposed to attach the defibrillator in the following way:

Since the AED drone has a camera and operator he is the one who times the shock pauses needed. After a while, hopefully the person suffering from heart attack has recovered, an ambulance arrives at the site. That is when the AED drone is no longer needed, and is returned to it’s base.

State of the Art

Currently the state of the art of drones is by the military, however, consumer drones have taken quite a leap forward as well. The current drone has 3 x 2 rotors, which create a lift capacity of 6 kg, and a maximum speed of 80 km/h. The current lift is enough, but the speed can be improved. One way of doing that is changing to a glider or a transfer design, or have more powerful motors. Another addition to the drone could be add a sonar, such that the drone can evade obstacles, which is difficult to do with only having a GPS.

Planning

Milestones

• First presentation: 1-05-2017
• Second presentation: 26-06-2017
• Finish defining problem statement: 3-05-2017
• Finish literature study: 22-05-2017
• Finish model: 11-06-2017
• Finish Experiment: 11-06-2017
• Finish Wiki: 18-06-2017

Gantt Diagram

Weekly updates.

New Planning for the final 5 weeks

Week 4: Make arrangements for the experiments (drone, room, people, pick a date for next week)

• Do try-out experiments (try the experiments on ourselves)
• Improve experiment plan (make it very explicit, step by step)
• Processing results (hypothesis, what to do when we actually get the results?)
• Check our wiki with the original planning

Week 5 (only Monday, Tuesday, Wednesday):

• Perform experiments on test people
• Analyze first data

Week 6:

• Perform experiments if we don’t have enough data yet
• Analyze and process data

Week 7:

• Complete analysis of the experiments and connect the correct conclusions to them.

Week 8:

• Finalizing everything (presentation, wiki, evaluation, follow up research)

Week 9:

• presentation

Experiment Plan

Code of Conduct for Drones

When dealing with an ambulance on the road, there are certain rules that apply to that situation to make sure the ambulance can get through the traffic as quickly as possible. Examples of this are: moving to the side of the road when an ambulance with sirens on is behind you, waiting for an ambulance to cross an intersection (even if you have the green light and the ambulance does not) and making as much room as possible in the middle of the road when you are in a traffic jam and an ambulance approaches. When it comes to drones, there are no such guidelines. This is most likely the case because drones are such a new technology. However, as drones are being used more and more, there should be a general code of conduct. This means that the drone as well as the people in its surroundings have a clear idea on how to behave.

When it comes to legislation, drones are categorized as model planes. This means the most important rules that apply are the following:

• Only fly during the day
• Make sure the drone can be seen from where you're controlling it
• Never fly above 120 metres
• Know the specifications of your drone
• Never fly above buildings, roads and people
• Never fly in no-fly zones like airports
• Always give way to other air traffic
• Never use a drone for commercial ends
• Respect other people's privacy
• Use your drone responsibly

Even though these rules give an indication of how to use drones in a legal way, it does not say anything about the situation we are trying to investigate. When looking at the rules that apply for an ambulance on the road, the most important tips for other drives were the following:

• When on a roundabout, stay on there until the ambulance has left the roundabout. This gives an easy opportunity for the ambulance to overtake you.
• Leave a lane open, this gives the ambulance a clear path through.
• Keep distance to the driver in front of you, so that you can move out of the way if necessary.
• Leave the emergency lane open.
• Don't exceed the maximum speed.

When looking at these rules, we decided to come up with the following rules for a crowd of people coming across the ambulance drone:

• Make space for the drone by moving to the right. This is essentially the same as the rule ambulances on the road use. If everyone moves to the right, there will be open space in the middle.
• Notify fellow pedestrians that a drone is coming their way. The more people know the drone is approaching, the more people will make room for it.
• When the drone wants to land near the patient, all people around the patient should make room at the patient's feet. This is important, because the drone might not be able to land as smoothly as it would like, mainly because of the fast speeds at which it moves. If the landing fails, the drone will crash onto the patient's legs instead of onto the patient's head.

These 3 simple rules will make it easier for the ambulance drone to find its way to the patient in a quick and efficient way.

Code of Conduct for Experiments

Laws and regulation in the Netherlands

• Hoofdstuk 2, Paragraaf 2. De verwerking van bijzondere persoonsgegevens
  • Artikel 16; De verwerking van persoonsgegevens betreffende iemands godsdienst of levensovertuiging, ras, politieke gezindheid, gezondheid, seksuele leven, alsmede persoonsgegevens betreffende het lidmaatschap van een vakvereniging is verboden behoudens het bepaalde in deze paragraaf. Hetzelfde geldt voor strafrechtelijke persoonsgegevens en persoonsgegevens over onrechtmatig of hinderlijk gedrag in verband met een opgelegd verbod naar aanleiding van dat gedrag.
  • Artikel 23; Het verbod om persoonsgegevens als bedoeld in artikel 16, te verwerken ten behoeve van wetenschappelijk onderzoek of statistiek is niet van toepassing voor zover:
    • het onderzoek een algemeen belang dient,
    • de verwerking voor het betreffende onderzoek of de betreffende statistiek noodzakelijk is,
    • het vragen van uitdrukkelijke toestemming onmogelijk blijkt of een onevenredige inspanning kost en
    • bij de uitvoering is voorzien in zodanige waarborgen dat de persoonlijke levenssfeer van de betrokkene niet onevenredig wordt geschaad.
• Hoofdstuk 5. Informatieverstrekking aan de betrokkene en de meldplicht bij inbreuken op de beveiliging van persoonsgegevens aan het College
  • Artikel 33
    • 1 Indien persoonsgegevens worden verkregen bij de betrokkene, deelt de verantwoordelijke vóór het moment van de verkrijging de betrokkene de informatie mede, bedoeld in het tweede en derde lid, tenzij de betrokkene daarvan reeds op de hoogte is.
    • 2 De verantwoordelijke deelt de betrokkene zijn identiteit en de doeleinden van de verwerking waarvoor de gegevens zijn bestemd, mede.
    • 3 De verantwoordelijke verstrekt nadere informatie voor zover dat gelet op de aard van de gegevens, de omstandigheden waaronder zij worden verkregen of het gebruik dat ervan wordt gemaakt, nodig is om tegenover de betrokkene een behoorlijke en zorgvuldige verwerking te waarborgen.
• Hoofdstuk 6. Rechten van de betrokkene
  • Artikel 35
    • De betrokkene heeft het recht zich vrijelijk en met redelijke tussenpozen tot de verantwoordelijke te wenden met het verzoek hem mede te delen of hem betreffende persoonsgegevens worden verwerkt. De verantwoordelijke deelt de betrokkene schriftelijk binnen vier weken mee of hem betreffende persoonsgegevens worden verwerkt.
    • Indien zodanige gegevens worden verwerkt, bevat de mededeling een volledig overzicht daarvan in begrijpelijke vorm, een omschrijving van het doel of de doeleinden van de verwerking, de categorieën van gegevens waarop de verwerking betrekking heeft en de ontvangers of categorieën van ontvangers, alsmede de beschikbare informatie over de herkomst van de gegevens.
    • Voordat een verantwoordelijke een mededeling doet als bedoeld in het eerste lid, waartegen een derde naar verwachting bedenkingen zal hebben, stelt hij die derde in de gelegenheid zijn zienswijze naar voren te brengen indien de mededeling gegevens bevat die hem betreffen, tenzij dit onmogelijk blijkt of een onevenredige inspanning kost.
    • Desgevraagd doet de verantwoordelijke mededelingen omtrent de logica die ten grondslag ligt aan de geautomatiseerde verwerking van hem betreffende gegevens.

Setup

Personal space with a drone

Method

Design

Often in literature, the personal space of a person is described as a bubble. However, there has been no study exploring the vertical personal space. This experiment focuses on the personal space in relation to a drone, which is significantly different than a human, since it makes noise and can create detectable downdraft because of its propellers.

Goal

The aim of this experiment is to approximate the personal space of a person when a drone is trying to land from above.

General setup

Place the test person standing up in a good open spot under minimal windy conditions. Let the drone slowly decent from a height where there is certainly no discomfort caused by the drone for the test person. The test person is free to move their head freely, but is requested to remain stationary as long as comfortable. When the test person either indicates the drone to stop, the drone is stopped and the height from the ground to the drone is measured. The test is repeated for different approach angles (behind, front, right above, right, left, etc.). For each approach angle, the participant indicates the preference of the approach by a Likert scale.

Information beforehand (subject)

• Length of the person
• Current field of study/occupation
• Experience with drones
• Age
• Right or left handed

Information beforehand (drone)

• Weight
• Size (length, width and height)
• Downdraft
• Noise production (in dB)

Subject movement

For this experiment, we ask the subjects to stay in one place and not to move their shoulders. They are free to move their head freely.

Variation

Since the variation in the decision making by the subjects can vary, each trial is repeated 3 times.

Approach angles

Personal space depends on the angle of approach. Since the angle of approach of the drone varies depending on the situation, the approach angles should not be restricted to the reference frame of the person. We use approach angles right above the person, North, South, East and West of the person. The drone descends straight down. For the horizontal distance from the person for the angles where the drone is next to the person, we use the distance found by Torta E. et al. for robot personal space for people standing up, which is 173 cm. Since we try to intersect this personal space zone, we use a horizontal distance of 1 meter from the person.

Approach Height

Experiments with drones and birds have shown that from an approach height of 30 meters, birds rarely react to the drone and often are undisturbed by the drone from a distance of 4 meters. For this experiment, we start at a height of 10 meters and if results show that this is inadequate, or excessive, we adjust this height accordingly.

Processing the data

We collect data for the distance of the drone to the ground when the drone is stopped of all different approach angles. With this data, \we plot two graphs. One graph for the height of the drone to the ground and the other graph for the height of the drone to the length of the person. We also plot the correlation between the height of a person to the distance at which they stopped the drone via a linear regression model. We test the significance of this regression via an ANOVA test.

Todo

• Equipment
• Hypothesys

Individual evasive movement

This experiment explores the instinctive movements by individuals in order to get out of the way of a landing drone.

General setup

The setup is similar to the setup of the 'Personal space with a drone' experiment described above.

Aim

How and when (Flight distance) does an individual move to get out of the way of a landing drone.

Main points of interest:

• When does the person get out of the way and does this approach the personal space model from the previous experiment?
• To which direction does the person move in order to get out of the way?
• Does the drone approach direction influence this direction?
• Where does the person look?

Processing the data

This experiment uses a more elicitation approach. Use an agreement score for the direction and specific movements of the persons.

Meeting notes

Week 1

Presentation feedback:

• Sounds: Where does it come from (specific sound)
• Etiquetes of behaviour: how people should react (not yet established for drone ambulances)
• Catching a drone instead of landing it
• What is the need: What is the current availability of AED's
• When should the drone create noise (if any)
• What will we add to the existing product of TU Delft
• Where did TU Delft reasearch stop

Week 2

After the presentation, what is the definitive direction of our project?

Most studies about crowd movement focuss on an non-interruptive environment where fluid dynamics can be used in order to model the behaviour. We want to focuss more on the human aspects, which are unpridictable agents.

We make a map of available AEDs in Eindhoven and when they are still available for use to illustrate the problem. What is the survival chance?

• Experiment:
  • Rules and Regulation: (Nikolay & Patrick)
    • Privacy
    • Criminality
    • Safety (weather)
    • Liability (assuming it is autonomous
  • Experiment plan (Rense & Wessel
    • Code of Cunduct (of the tu/e)
    • Reasoning (+Hypothesys)
    • Experiment Setup

Update Wiki (finilaze problem statement etc.):

• Thom

Next meeting: 8-5, 11:15, MF15

Week 3

Meeting May 8th

The problem statement is vague and inaccurate:

• Provide a more concrete problem statement
• We described law, but it is not part of the problem statement (best to not include it at all, since it is not actually relevent to our project)
• Perhaps skip the ethical part
• Focuss more on landing as fast as possible In a human acceptable way
• How much 'fear' or 'panic' is acceptable in order increase the landing speed.

Experiment:

• Perhaps perform an experiment with a crowd
• Perhaps do the experiment in Delft?
• What if the drone arrives early?
• Prevent interference of bystanders

USE:

• Are there exceptions for ambulance/police drones currently?
  • Perhaps there are interesting rules for ambulance helicopters
• Are there exceptions for unmanned aerial vehicles?

Other:

• A map of AEDs is a good introduction to the problem statement, and what is the best strategical placement of the drones.
• Who currently pays for the AEDs?
• Perhaps recommend rules and regulations in our conclusion
• Rules and regulations should not be our main focuss in this project

---

Next meeting:

• Read the ambulance drone paper (on the drive) - All
• Rewrite problem statement
• Improve Objectives - Nikolay
• Further elaborate Users - Patrick
• Setup of the experiment - Wessel
• State of the art (paper) - Thom
• Look up robot experiment examples - Rense

Next meeting: 10-5, 10:00 in OGO2

Meeting May 10th

• State of the art of the drone (TU Delft paper) - Patrick
• Map (why do we need drones) - Thom
• Theory (How do EADs work, using the drone from start to end) - Nikolay
• Elaborate USE part - Rense
• Experiment (further elaborate the options) - Wessel

Week 4

Meeting may 15th

• Look at a previous group who did package delivery with a drone
• Perhaps incorporate approach velocity in the experiment
• Make sure we have a good end product in mind
  • Keep all tasks relevant to the end product
    • Take technical implementations from Delft for granted
• For the experiment setup, formulate how to process the data
• Formulate in general better questions regarding the project
  • Why are we doing this? Is it relevant? ... etc.
  • How are we going to achieve the goals
  • Split problems in smaller parts (Divide and conquer)
• For the drone, contact Duarte Antunes (D.Antunes@tue.nl)

References

Code of conduct: https://www.drones.nl/wetgeving http://wetten.overheid.nl/BWBR0019147/2015-11-07 https://www.anwb.nl/verkeer/veiligheid/wat-te-doen-in-verkeer-bij-sirene-en-zwaailicht