If you need auto assistance, you should generally enquire with your insurance company, as they will usually have made arrangements with a local company. If they haven't try one of the following companies, but expect to pay € 100-300 for a simple service like towing to nearest shop.
Scandinavian Airlines (http://www.scandinavian.net/), Norwegian (http://www.norwegian.com) and Cimber Air (http://www.cimber.dk/) all operate domestic routes, all of them either from or to Copenhagen Airport, there is no domestic routes between regional airports. Since most of the country's airports were build as military airfields during the second world war, they are often inconveniently located far from town centres, which as a general rule make train travel nearly as fast from town centre to town centre for destinations less than 3 hours by train from Copenhagen. For destinations further afield trains will often get you where you want to go a lot cheaper, albeit competition is heavy, and it is indeed sometimes possible to find plane tickets cheaper than the train, if you book well ahead of your planned departure - this is especially true for the Copenhagen - Aalborg route, where both traffic and competition is heaviest.
Airports with domestic traffic are: Copenhagen, Billund, Aarhus, Aalborg, Karup, Sønderborg and Bornholm.
Some of the more remote islands, if there is any such thing in a country as small as Denmark, also sees regular taxi flights from Roskilde airport to their small airfields, on-board small propeller aircraft. The most traficed route are between Roskilde and the islands of Læsø and Anholt, where there are daily flights bookable on-line or by phone. These flights tend to be fairly expensive though, with the price hovering around 1000 DKK for a one way ticket.
Long distance train travel is done with DSB, the Danish State Rail system. (http://www.dsb.dk) A number of long distance bus companies also operate. Each region in Denmark has its own local public transportation company. For public transportation trains, buses and ferries use the online travel planner Rejseplanen (http://www.rejseplanen.dk...)?. There are two ways to buy tickets. For local trips you can buy a ticket from the regional transportation company based on a zone system. This ticket is valid on all public transportation including DSB trains for one to two hours depending on the number of zones you travel. Most public transportation companies offer a number of passes which can save you a substantial amount on transportation. In the greater Copenhagen region, the zone system is complemented by a system of “klippekort”, punch cards. These cards come in a variety of colors where the color signifies the total number of zones one can travel through for each punch. So a two zone card punched once allows one an hour of travel throughout two zones. A two zone card punched twice in the same machine is valid for travel in four zones or from the airport at Kastrup to the main train station in Copenhagen. DSB also uses a similar system of klippekort/punch cards for travel in the Oresund region.
To use a klippekort/punch card, you insert the card, face up, into the yellow machine on the train platform. You will hear a clunk as a punch discard is removed from card. Repeat to add zones. The machine will also have a zone map and a guide to explain how many punches it takes to travel from where you are to where you want to go. Most regions have their own klippekort but they do not work between regions. Some of the long distance bus companies offer klippekort that are valid for a specific route across regions but these are probably of little use for travelers as they have to be bought on cards of 10 punchestrips.
The only way get to most of the smaller islands, is by ferry. There are 55 domestic ferry routes in the country. The two most important ferry companies are Nordic Ferry (http://www.nordic-ferry.com/) and Mols Linien (http://www.mols-linien.dk...).
Ferries are the best way to get to Bornholm, a Danish island in the Baltic Sea, although it also can be reached by plane. Since the opening of the bridge to Sweden, the easiest route from Copenhagen to Bornholm is by train and then ferry from Ystad. Through tickets are available from Copenhagen and Ronne - booking is mandatory. There is also a bus that serves this route - Gråhund Bus 886 from Copenhagen to Ystad, where it links with the ferry to Bornholm
Biking in Denmark is, in general, safe and easy. Drivers are used to bikes everywhere, and all major cities have dedicated, kerbed bike lanes along the main streets. Denmark is quite flat, but can be windy, cold or wet on a bike. Bikes are generally allowed on trains separate ticket sometimes needed.
Note that biking on the expressways Da: motorvej is prohibited, and that this also includes the Great Belt Bridge and the Øresund Bridge. Trains can be used between Nyborg and Korsør and between Copenhagen and Malmö if you need to cross the bridges.
Official marked routes across the country can be found in the guides on this page: (http://www.trafikken.dk/w...)
It is quite easy to hitchhike in Denmark. People who pick up hitchhikers usually speak English. Destination boards are recommended. It is illegal to hitchhike on the highways, so it is better to use highway-entrances and gas stations. When crossing by ferry, try to get into a car that already paid for the ticket.
If you hitchhike from the southern part of Denmark direction from Hamburg or Kiel, Germany, and continue in direction to Copenhagen, make sure the driver doesn't stop in Kolding. If he does, ask him to stop at the last gas station before Kolding. On the Kolding highway crossing there is no place to hitchhike and it is one of the worst places in Europe for hitchhikers.
Check out the Tips for hitchhiking article here on wikitravel if you are new to hitchhiking.
The primary Danish train company is Danish State Railways or DSB (http://www.dsb.dk). Many feeder lines for the principal train line in eastern Jutland are now operated by British company Arriva. Other small rail lines are operated by other companies. DSB also operates the S-Tog commuter rail system around the greater Copenhagen area. Eurail passes are valid on all DSB trains. Danish trains are very comfortable, very modern and very expensive. Tickets can be purchased in stations, from vending machines in the stations and via DSB's website. In addition to a ticket, some trains require a seat assignment. Most trains have 230V power outlets.
If you are not travelling on a rail pass, try asking for a Orange ticket, these are a limited number of heavily discounted tickets that are available on most departures. They are often sold out way in advance, but it never hurts to ask - and you do need to ask, in order to get the discount. Unfortunately due to worn out rails, the intercity trains are often late, though as many other railways suffer from similar issues, this is of course very relative, and both funding and a comprehensive DKK 36 billion plan to deal with the problem, has passed through parliament, although it will take many years to remedy years of neglect. All trips with trains and local buses can be scheduled electronically through Rejseplanen.dk (http://www.rejseplanen.dk...)?.
Driving in Denmark between cities is very easy, with well-maintained roads everywhere. Danes generally drive by the rules, but may not be very helpful to other drivers in ceding right of way, etc and stick very rigid to keep to their rights. There are no toll-roads except the two big bridges: Storebæltsbroen (http://www.storebaelt.dk/) between Zealand and Funen DKK 215 one way, and Øresundsbron (http://www.oeresundsbron.dk) between Copenhagen and Malmö DKK 235 one way.
Touring Denmark by car can be a wonderful experience and highly recommended. Margueritruten The Marguerite Route (http://www.visitdenmark.c...) is a 3500 km long connected route of small scenic roads passing 100 important Danish attractions. It is marked by brown signs with the white Marguerite Daisy flower and is also marked on most roadmaps.
Unless otherwise posted, speed limits are 130 km/h 80mph on the motorways, 80 km/h 50 mph outside build-up areas and 50 km/h 30 mph in built-up areas. Although the limit goes up to 130 on intercity stretches, large stretches of motorway around cities, major junctions and on the inter-island bridges have limits of 110 km/h or lower. Vehicles with caravans or trailers as well as trucks are limited to 80 km/h on motorways, 70 km/h on roads outside build-up areas and 50 km/h in build-up areas, even though other speed limits may be indicated. Speeding occurs frequently, especially on motorways, though recent years dedicated effort by the Danish police on speeding, has made more people aware of speed limits. Trucks in Denmark generally do 90-ish km/h on motorways and trucks overtaking each other on long stretches of motorway collegially known as elephant races occurs frequently. Fines ranges between DKK 500 € 70 and 10,000 € 1,370 and driving ban in Denmark.
Driving across the over-sea bridges can subject your car to very strong gusts of wind, and when overtaking lorries or close to bridge support columns these can be anticipated. Drive at a speed that allows you to make course corrections to stay in your lane.
Wearing seatbelts in cars and vans is compulsory if fitted, and children under 135 cm and or under 3 years of age, must use approved safety seating devices adapted to their height and weight.
Headlights must be switched on when driving at all times and dipped during sun hours, regardless of weather conditions or whether it is a night or day, so switch them on. If your car has the new Daytime Running Lights, which are small but bright lights on the front only, that are different from headlights, these are enough until twilight. But turn on your headlights in fog or rain, and know that DRLs only light the front.
Drivers and passengers of motorcycles and mopeds must all wear full face helmets.
Though required under law, little use is made of indicators on roundabouts, so generally if the car isn't indicating it is leaving the roundabout, give way as it is invariable going round. When changing lane on motorways use of turn signals prior to- and during overtaking is mandatory.
On open roads, especially those with an accompanying cycle path, expect drivers turning right to come to almost a dead stop, which they check to see they are not cutting up a cyclist, even if there is no way even an Olympic cyclist could appear from nowhere on an entirely cycle free horizon.
Denmark allows drivers to have 0.05 percent alcohol in the bloodstream while driving for most people this is equivalent to having consumed one drink or less, and Danish police is very aware of possible drunken drivers. Fine is calculated as percent of alcohol in blood × 10 × your monthly salary before tax.
Watch out for the bicycles in the cities, especially when turning across bicycle lanes, the bicycles always have right of way. Special care should be taken at Roundabouts !.Cyclists in general seem suicidal to drivers from other countries, as they will not look, or slow down if turning onto the road in front of you. After sun hours, lights on bikes seem to be voluntary - especially in the bigger cities - even though it is in fact compulsory.
You must always carry your driving licence, vehicle registration document, and certificate of motor insurance in the car. It is compulsory to have a Warning triangle in the car, and to use it if you experience breakdowns on highways or on regular roads where you are not able to move your car out of the way.
Ease of driving inside cities is a different story. Congestion in and around the major cities, especially during rush hours can be a trial for some people. If you are in your own car, it is wise to park it in a convenient central place and walk or use public transport, bike or taxi to get around the big cities. Most parking areas requires the use of parking discs/parking clock faces in Danish parkeringsskiver or "P-skiver" in short which must be placed in the right side of the front window, with the clock facing out of the window and the hour hand set to the time you park there is no minute hand.
Some places require a parking ticket from a nearby parking ticket vending machine to be placed in the car, in the lower right corner of the dash-board, readable from outside the car. Some more modern parking ticket systems allow the purchase of parking tickets using text-messages from cell-phones, though this can be a very expensive affair from foreign numbers. The majority of the parking ticket vending machines, accepts international credit and debit cards, however this is still a large quantity that only accepts Danish national credit cards or coins. Note that in some areas - especially in the Copenhagen area - have multiple vending machines with different parking coverage. In this case the coverage is indicated with a map on left or right side of the machine. Be sure to check that the machine you purchase a ticket from, actually covers the area you have parked.
Though renting a car in Denmark is a relatively expensive way to explore Denmark, it is convenient, efficient and particularly useful if you intend to visit more remote areas, where train and bus services may be less frequent. Prices starts a approx. 120€/day at the big car rental chains, but with limited mileage, typically 100 km per lease and an additional 25 km/day. It is not uncommon for the car rental chains to require the drivers to be at the age of 21 or higher and require that payment be done with an international credit card.
Be aware that Scandinavia is no exception to the widespread European scam of adding hidden charges to your car rental bill, and not including services like auto assistance. Also, unlike other goods and services, quoted car rental rates may not include the 25% V.A.T. or sales tax for purchases by private people. Carefully read the rental agreement before you accept your car.
If possible renting a car in Sweden just across the Sound from Copenhagen and Elsinore or Germany just south of the border in Jutland can be an economically sound move. Car rentals in Sweden and Germany are less than half the price of Danish rentals and mostly comes with free mileage. Remember to check if the rent allow for driving in Denmark and what auto assistance is included.
Long distance bus-service between Jutland and Copenhagen is possible with the company Abildskou line 888 (http://www.abildskou.dk/), and while cheaper than the train, the difference is less pronounced than in many other countries, A ticket between the country's two largest cities; Aarhus-Copenhagen for instance, is DKK 270 one way for adults with Abildskou versus DKK 350 with the train. If you are flexible there is considerable discounts available in certain departures, where tickets can get as low as DKK 180, if you buy your tickets in advance.
See also the overview at: Fjernbusser.dk.