Installing a video surveillance system on a fleet of buses or light rail system can be a massive undertaking, especially if your transportation network is very large.
While onboard surveillance systems are now commonplace in North America and around the world, most industry experts agree that not all systems are built the same.I frequently field questions from operators who are confused about what to install and why, given the many options on the market.
I advise them to first consider their main objectives for installing video. Are you trying to reduce false liability claims? Are you attempting to improve safety by discouraging criminal activity? Do you want to respond more quickly to emergencies?Or maybe you’re hoping to address HR issues by monitoring employee performance? Maybe it’s all of the above? It’s important to think about why you want video surveillance and what your primary use will be, as this will guide your system design.
I also recommend reviewing the American Public Transportation Association’s (APTA) technical standards for CCTV systems on transit vehicles. The recommendations are designed to promote best practices in the industry, and ensure the quality of images captured by mobile surveillance systems are of use to operators.After all, there’s little sense in installing a surveillance system that doesn’t work, or that delivers poor images that are of no use to police or any other investigator.
Here are three key takeaways that can help you maximize the benefits of your onboard surveillance system.
1. Know the Minimum Resolution You Need
Camera technology is constantly evolving and today there’s a myriad of options for mobile video surveillance. But it’s important to understand how the cameras you choose will affect your image quality.
While a lot of transit agencies are still deploying analog cameras, many are upgrading to IP. Recent advancements in technology have improved IP camera lighting performance, so a good quality mobile IP camera can now exceed the lighting performance of an analog camera with IR technology.IP cameras also offer more flexibility in terms of system design and recording options.
APTA’s CCTV standards recommend that transit operators use IP cameras with a minimum recording resolution of 1080p.Scenes with slow motion (for example, where someone is walking) should be recorded at 5 frames per second (fps) while scenes with fast motion (such as vehicular traffic) should be recorded at 30fps.
If you’re still using analog cameras, your minimum resolution should be at least 4CIF/D1. However, you should expect lower image quality when you’re using this resolution.
If you’re a public transportation authority, you may be required to supply evidential video to a court if an incident occurs on one of your vehicles. Evidential video must be high quality, and clear enough to be used in an investigation, hence the recommendation for 1080p.
If you’re concerned about how this impacts your storage, remember IP cameras can record alternate streams of video – one in high resolution for evidential purposes and one in a lower resolution for operational purposes. Evidential video must be high resolution; however, operational video – or the video you use to monitor everyday operations – can be recorded at a lower resolution and compressed for transmission over a network.
2. Consider the Minimum Storage Period You Require for Video
When determining your storage requirements, it’s important to think again about why you’re installing video surveillance.If your goal is security-related, you should learn your state and federal regulations for retaining surveillance video, and also consider any privacy laws that may apply.
In the U.S., APTA recommends that evidential video be recorded locally and retained on your vehicle for 7 days. This allows sufficient time for an incident investigation to take place and for an operator to determine if they need to remove the high resolution images from the vehicle for safe keeping. In order to retain this amount of video, ensure your mobile network video recorder (NVR) has enough terabytes of storage, or if you’re on a network, you can use a Network Attached Storage (NAS) device.
A longer period, 31 days, is recommended for retaining video in fixed locations like stations, depots or control centers. Remember, all video used for evidential purposes must be untouched, unedited and contain a digital signature to verify that no video tampering has occurred.
It’s important to balance your recording resolution with your recording duration, otherwise you risk depleting your storage capacity. Most systems today use H.264 compression technology to do this. In mobile IP video surveillance, low latency is important as delays in viewing images can present safety issues. Your system should ensure the period between I-frames (also known as key-frames) is no more than 10 per second.
3. Determine if You Need to Backhaul Video off Your Vehicles
In the video surveillance industry, the term “backhauling” refers to the digital transmission of video from your mobile recorder to your control center.It can be a convenient way for transportation agencies to view what’s happening inside a vehicle, and it can also speed investigations, since video is transported wirelessly over a network, rather than manually removed from an NVR’s hard-drive.
As an operator installing or upgrading a surveillance system, you need to decide if the ability to backhaul video is a requirement for your system.
If it is, you’ll need to decide what network to use, and consider the technical and financial implications involved.Constructing a private network can be costly. Using WiFi is less expensive, but can pose limitations since your fleet needs to be near WiFi hotspots in order to backhaul video. Whatever network you use, sufficient bandwidth is required to transmit large megapixel data. This is especially true if you’re considering capturing additional vehicle data like GPS location or integrating your video with your fleet management system as many operators are now doing.
Often, it boils down to the amount of data you want to backhaul.
For operators using video for security and crime reduction, most solutions including March Networks RideSafe include an option to “tag” video of an incident, so it’s stored in the NVR for safe removal. RideSafe also enables the automated extraction of that video over a WiFi or 4G network. This gives a transportation agency fast access to video evidence following an incident, while also safeguarding the original, high-resolution video on the NVR for investigative purposes.
As we’ve just learned, there are many things to consider when installing or upgrading video surveillance on your bus or light rail system, but being able to answer the above three questions can help you design the right kind of system for your agency’s needs. Remember to always think about your main reason for installing video surveillance, and consult APTA’s CCTV guidelines if you need more information on industry standards.
Dave Gorshkov, CEng, FIET, is the chairman of APTA’s Communications Sub-Committee Technical Standards Working Group and CEO of a UK-based technology focused business consultancy practice.He advises a number of US, UK and international-based rail and mass transit authorities, ministries of the interior (MOI) as well as major transportation systems companies and government transport agencies on various aspects of security technology including the latest generation of digital CCTV, intelligent video, Safe City architectures and wireless systems applications.