Safety in numbers

Thinking Highways
By Ariana Drivdahl May 13, 2014 14:46

Safety in numbers


Using wireless technology for smarter safety for buses and other modes of transportation, by Ariana Drivdahl.

When it comes to transportation safety, most people think about the basics – do my brakes work, is my seatbelt functioning properly, is the highway smooth and free of hazards? Beyond these basics, ensuring transportation safety requires the ability to know and respond to any abnormal circumstances that affect the safety of passengers or surrounding vehicles. Tools like in-vehicle and electronic roadside signs alerting drivers of danger are increasingly relied upon to ensure public safety. On demand or constant communications have become a necessity for operators to make the best use of these tools, and there are different ways to achieve these communications.   The predominant types of communications are Wi-Fi (both traditional frequencies and public safety frequencies) and cellular technology.

As an example, access to live in-vehicle video surveillance feeds would be invaluable for authorities to respond quickly and effectively to a vehicle emergency or hostage situation on a public bus. High bandwidth wireless technologies are now making it possible to stream live video surveillance from a vehicle to a command center. This not only allows authorities to see what is happening in real-time, it allows for them to formulate and execute a plan of action.

Quality Image, Durable Hardware

Onboard video streams from buses and other public transportation vehicles are increasingly being sent from cameras that deliver high-resolution streams and are designed for harsh environments. Because some cameras are also installed on the outside of the buses, it is crucial they are able to withstand the same type of environmental conditions as the bus itself, whether that be in searing heat or freezing cold. When this type of a camera network is connected to a wireless access point, the access point and its corresponding antennas need to be graded to the same degree of durability.

Putting Security First

Older forms of wireless communication have known security weaknesses, but these issues have been addressed with updates in wireless technology that allow for secure operation. Using the 4.9GHz frequency, which is governed by the FCC and reserved for public safety applications, users can ensure that standard wireless devices will not be able to connect to that network as they do not support that frequency. This ensures that not only will traffic sniffing will be eliminated, but that bandwidth can be prioritized for that safety traffic. Users simply need to work with the FCC to obtain permission to use those frequency bands. In addition, with the advent of dual radio technologies (having two independent radios in one unit), one radio on an access point can be reserved for the “live” video surveillance feed accessible by authorities only, while the other radio can be opened up for public use, (eg web access to passengers, downloadable video feeds, user information and so on).

Higher Bandwidth, Better Video

With the advent of 802.11n, which supports much higher bandwidths than older 802.11 protocols, it is possible to network many cameras on the bus, whether they are inside, outside, or both. Reaching speeds of up to 300Mbps, this is the perfect protocol to use when streaming video, as it can handle multiple video streams at a time without sacrificing quality. Additional specifications in the 802.11n protocol allow for more reliable communication as well as increased range, making it for this type of application.

Aside from ensuring the safety of passengers and operators, high-bandwidth wireless communications can provide additional benefits. For example, it is an excellent way to retrofit old buses to bring them into modern communications. As budgets get tighter and tighter, local transportation authorities are seeking ways to bring their old equipment into line with newer equipment. High-bandwidth wireless communications is a relatively simple retrofit of older buses, light rail, and trains, extending their useful life while still allowing them to communicate effectively with modern interfaces.

Adoption Across Multiple Industries

With relatively simple modifications, wireless can be applied to many different types of applications. For example, in a metro or underground scenario, it is possible to install leaky coax along the length of a track to ensure constant communications. In a taxi scenario, a camera can be tied to a cellular modem to provide constant monitoring if needed.

The downside to Wi-Fi is that its range is limited; unlike longer-range technologies like cellular, satellite, or 900 MHz, Wi-Fi only works in the general area that it’s installed in. If you are looking to cover a large area, the cost of installing Wi-Fi can certainly be large.   However, Wi-Fi’s flexibility, high security, and fast speeds make it ideal for many safety and transportation applications.

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Thinking Highways
By Ariana Drivdahl May 13, 2014 14:46