IFB versus RFP

Invitation For Bid (IFB) versus Request For Proposal (RFP)–is the least expensive really the least expensive?

What is an RFP?

An RFP is a public solicitation for goods and or services. The RFP relies on a generalized scope of work to outline the desired deliverables. Vendors will prepare a response in a given timeline that best meets the needs of the agency as defined in the scope of work. The agency will then be able to award to the ‘most responsive’ vendor in accordance with a set of predefined criteria.

As RFPs are typically performance based solicitations, with open methods of execution, this allows for variations in the quality, service and price. In this, stronger products and/or services are able to differentiate themselves with enhanced performance over a straight price comparison. The end result is a product and/or service that the agency will be the most satisfied with.


  • Quick and easy scope of work writing
  • Selection based on optimal performance
  • Open to innovation and industry enhancement
  • Allows for negotiation to obtain best value
  • Customized for the agencies needs
  • Considers overall cost versus initial price


  • Lengthy evaluation process
  • Potentially higher priced responses


  • Solar powered lighting systems for bus stops
  • Buses
  • CAD/AVL systems
  • Bus shelters

What is an IFB?

An IFB is a public solicitation for a very specific good and/or service, which can be equally supplied by many different vendors. Unlike the RFP, the IFB requires a very specific scope of work with highly detailed deliverables. Vendors will respond with a straight price for the specific product and/or service to be provided. The bid will be awarded in accordance with the lowest responsive price.

IFBs are strictly price based solicitations and require agencies to have expert knowledge of the product and/or service it is expecting to receive. It is not unusual for responses to be rejected due to lack of conformance with the strict criteria outlined in an IFB. Through this method of procurement, agencies ensure they receive the lowest price for products which are widely available.

In the event that an agency desires to undergo an IFB process for a specific product, the product must be available to be purchased by any and all responding parties. It is then that a product may be specified with options for approved equals. It is at the discretion of the agency’s procurement team to define comparable traits and minimum characteristics for an equal product. This comparison process typically requires an individual with extensive experience and knowledge of both comparable products.


  • Quick and easy award
  • Same product regardless of vendor
  • Lowest price
  • Ideal for large numbers of respondents


  • No performance factor
  • Non-specific to agency needs
  • Compliant to minimal standards
  • Specification can be difficult to develop
  • Potential for overall long term costs to be higher


  • Parts
  • Fuel
  • Installation of construction projects

RFP versus IFB

Both RFPs and IFBs have their advantages and disadvantages, and when used properly, each has their place in any industry.

In terms of developing the proper procurement practices for reliable solar lighting system design, RFPs are the natural preference. This is clear in terms of the low number of available solar lighting developers with each system having its own distinct characteristics, qualities and benefits.

Even the most experienced agencies may not be up to date on all the innovative ideas in the solar lighting world and how they differ from vendor to vendor. By using the RFP process, vendors are able to expand potential options to explore the existing systems as well as the newest and most innovative features to carry agencies far beyond the usage of today’s riders.

When approaching solar powered lighting through the RFP process, it still important to outline a minimum expected level of performance. The key characteristics that should be included in developing a successful RFP for solar powered bus stop or shelter lights are light levels, days of autonomy (battery capacity), controller features, operating profile, and mounting surface. Other factors to consider are warranty, references/experience, certifications and regulatory compliance.

Light levels

As night time light is the ultimate goal of a solar powered lighting system, it is important to establish a clear minimum level of expectation when releasing an RFP. Lumens are often talked about when you are looking for information about general lighting as lumens represents the total amount of light produced from a light source. The major problem with strictly looking at a lumen value for a given light fixture is that the light could be going in all directions or be highly concentrated in one spot.

That’s like comparing a light bulb to a laser.

‘Foot candles’ are the measurement of light at a specific point which is a set distance away from the light source. Foot candles for solar powered lighting are a better method of evaluating the difference between various vendors’ products as the critical area of illumination is typically the bench or shelter footprint. All light fixtures will give off peak, average, and minimum foot candles in a given surface area below the light fixture. Photometric plots, or IES files, will define the output in accordance with the agency defined surface area and distance from the light source.


This refers to the number of functioning days with no added power to the system through the solar panels, either as a result of poor weather conditions, solar panel coverage (snow, leaves, excessive dirt, etc), or solar disconnection/damage.

The minimum industry standard is five days or five nights of autonomous operation from a reliable solar powered lighting system from a full state of charge.  Calculations outlining the available battery capacity over the nightly power consumption will give you the days of autonomy. For example, if you have 40 amp hours of battery capacity and consume eight amps per night you have five days of autonomy.

Controller features

As controllers are the brain and central nervous system of a solar powered lighting system, there are ongoing upgrades and performance enhancements being made throughout the industry. It is important that there is a basic understanding of your agency’s desires of performance to develop a minimum specification.

All controllers will regulate the solar and allow for some degree of illumination transition. Features such as ‘Low Voltage Disconnects’ to protect deep cycling of batteries can be critical to highlight in order to ensure product longevity. Whereas features such as ‘Operating Profile Program Adjustments’ may vary amongst vendors in terms of execution and preference.

In an RFP, it is critical that the responding vendors clearly highlight the features and functionality of their controller and to educate through their response the enhanced benefits as they differ from a minimum benchmark.

Operating profile

Operating profile refers to the illumination as well as light levels during a given night. Often agencies chose dusk to dawn illumination for security lighting, with light levels scaled back when service is no longer operating. Advertising lighting is often split anywhere from four to six hours after sundown, and returns for two to four hours before sunrise. Only systems that incorporate a real time clock that self adjusts to daylight savings can provide such accurate profiles.

Mounting surfaces

The mounting surfaces and the proposed design will differ from vendor to vendor and can be used as a method of measuring conformance with the desired aesthetic. In most cases, agencies will want a low profile vandal resistant aesthetic for a system and its solar panel when installed onto a shelter, however, there are other instances where vendors may propose a pole mounted solar panel so their system conforms to a wider range of shelters. While it may appeal to have systems that conform to a wide range of shelter types, vandal resistant properties are critical for ensuring the longevity of a system. Secondly, as some solar powered lighting system providers have standalone bus stop pole mounted solar powered lighting systems, it is critical to define the existing pole type on which it will mount. Some vendors will only mount to their own or specific pole types and may not conform to your agency’s existing standards.


Urban Solar provides a five-year warranty from the delivery date. This warranty covers all parts of the lighting systems, excluding batteries which have a three-year prorated warranty.

A warranty is only as good as the company who is offering it. Experience with solar lighting, as well as how long a company has been in business, will help determine whether a proposer will be able to provide warranty assistance if needed in the future.


References can not only offer the opportunity to hear about the proposed vendor and system, but they can also provide insight into the experience these agencies have had with other vendors. Information or unknown criteria to look for may be found through their first hand experience. Industry standards typically request three to five references of customers using the same product.

Certifications and measurements

To assure expertise in a given field, certification and measurement documentation is needed. These allow agencies to compare and qualify vendors individually, as well as see how a proposed system came to be offered.

Examples of such certification and measurements documentation are ALR (Array to Load Ratio), Autonomy Calculations, Photometric plots or IES files, P.Eng docs (Professional Engineer Documents), UL (Underwriters Laboratories) certification, and NEC (National Electrical Code) compliance.

In an RFP, it is important that a vendor’s response incorporates the applicable and requested documents, so that an agency is equipped and educated of the vendor’s capabilities specific to the product being proposed.

More information

The APTA procurement handbook

The APTA transit procurement guide


Whether you choose to develop an RFP or an IFB for the procurement of reliable solar powered lighting systems for your agency, it is critical to establish the key components that are important for your purposes. Not all solar powered lighting systems are created equal and it is typically easier for an agency to engage in an RFP to encourage vendors to provide the best and most competitive system for your agency. IFBs can be used for the procurement of reliable solar powered lighting systems provided there is an individual in the procurement team with a high level of expertise and experience in developing solar powered lighting systems.

Examine your application, the products that exist and the products you are looking for. Measured and detailed performance criteria will allow you to receive technically sound and thoughtful proposals or offerings that will ultimately deliver the services and product to best serve your customers and provide long term savings.

From our customers:

“Urban Solar’s technology adapts to our short, overcast winter days and offers a remarkable and reliable product. It enhances passenger’s safety and operator visibility.”

– Jeff Brewster, Intercity Transit

“The new Urban Solar improvements and technology have increased ridership more than 20 percent and decreased costs by about 35 percent.”

– Richard Tree, Porterville Transit

“Initial costs to supply and install these lights are lower compared to conventional systems. We will do more of these installations as pathway lighting needs arise.”

– Gary Darrah, District of Saanich