Sample Essay on Criminal Justice


This report reviews the result of the National Academy of Science report on assessment of the development of new forensic technologies and a comparison of the new technologies with the old. Therefore, a detailed analysis of the Intoxilyzer 5000C and the Intoxilyzer 9000 has been undertaken. The Intoxilyzer 5000C, which costs $7500 for a single unit, with additional costs for the special print card, is currently undergoing a face out for the better performing Intoxilyzer 9000.Part of the reason for its facing out is its inaccuracies, which include 27 percent uncertainty in addition to overestimation of 23 percent of the subjects’ blood-alcohol concentrations. The report establishes the great improvement of the Intoxilyzer 9000 fitted with a full color touch screen, Ethernet and USB slots, in addition to expandable memory for storing test information. A further comparison of the two Breathalyzer technologies has also been undertaken, with a conclusion on the improvements made by the Intoxilyzer 9000 in accuracy, speed and reliability.

Intoxilyzer 5000C v. Intoxilyzer 9000: A Comparison

Forensic science has developed over the years to become one of the most important fields in solving crimes.  Methods of forensic investigation have also evolved to become more accurate and efficient, helping in the fast paced solving of crimes.  The evolution of the field (forensic science) has largely been necessitated by the continued sophistication in the nature of crime, as well as the need to solve crimes both quickly and with as little margin of error as possible. Moreover, the committee on forensic also played a pivotal role in the evolution of the field, in addition to the establishment of the Forensic Standards Board. This was a reaction to the “Strengthening Forensic Science in the United States: A Path Forward” report suggestion by the National Academy of Sciences on the establishment of the board, particularly goal i). The goal proclaimed the essence of the board in comparing current and previous Forensic methods, and “assessing the development and introduction of new technologies in forensic investigation” (Committee on Identifying the Needs of the Forensic Science Community 20). Of importance, are the value and accuracy of data provided by the method chosen particularly in solving cases. Blood alcohol content for example, is necessary in determining whether an individual was within the legal drinking limits and therefore determine charges of drunk driving and other similar offenses. Although there is a diverse range of tests for establishing blood alcohol content, the Intoxilyzer 5000C that uses infrared for measurement of alcohol in a breath sample has been in use, measuring the sample at three wavelengths with considerably accurate results (Watterson 109). The Intoxilyzer 9000 on the other hand, uses the same technology, but takes measurements within different wavelengths, with quicker responses. This paper will therefore make a comparison between Intoxilyzer 5000C and Intoxilyzer 9000, with an initial overview of the two technologies.

The Intoxilyzer 5000C is an infrared-based instrument for the measurement of ethanol in a breath sample. The instrument measures the absorbance of the infrared lights at multiple wavelengths of 3.39, 3.48 and 3.80 microns (Watterson 109). The three wavelengths perform different functions, which work together for the detection of alcohol levels. The 3.39 wavelength detects and quantifies ethanol in the breath sample, the 3.48 detects intrusive substances, while the 3.80 wavelength acts as a positional juncture. The IR detector of the Intoxilyzer 5000C for detection and adjustment of any possible interfering compounds uses the 3.39 and 3.48 wavelengths (Wigmore, Patrick and Libman 223).

The Intoxilyzer 5000C is an instrument with several chambers for inhalation and exhaustion of the inhaled breath. The electronic machine has a keyboard for keying in subject data, as well as a slot for the recording card used to store subject information (Wigmore, Patrick and Libman 218). At the turning on of the instrument, it requires about 15 minutes for heating to the requisite 450C and for the electronics’ stabilization (Wigmore, Patrick and Libman 218). The Intoxilyzer 5000C additionally has a screen for display of the technician’s interaction with the machine. The display is particularly instrumental in the display and correction of any error in the subject data as entered by the technician.

The machine has three valves and a pump, with the pump’s major work being the creation of a vacuum within the machine by sucking air through an internal breath tube, and out through an exhaust port (Wigmore, Patrick and Libman 219). These are usually standard tests meant to clear the instrument of any interference and make it ready to take breath samples for alcohol content testing. After the self-diagnostic tests, the instrument is ready for testing, and requires the subject to blow into the mouthpiece with sufficient pressure.  Any insufficiency in the blowing pressure will result in error messages. However, with satisfactory samples using sufficient pressure, the machine processes and prints out the test result within three minutes of taking the sample (Wigmore, Patrick and Libman 220).

The Intoxilyzer 5000C has an intelligent breath sampling system that caters for differences in age and gender. Thus, the machine can detect using the Forced Vital Capacity (volume of breath exhalable by a subject after maximum inhalation). Therefore, given the variance in FVC in relation to age, height and sex (males have a greater FVC than females; ages 20-40 have the greatest FVC; FVC decreases after 65 years; taller people have greater FVC than short ones), the Intoxilyzer 5000C sampling system accounts for these variances (Wigmore, Patrick and Libman 221). This it does specifically by adjusting the time required for blowing into the instrument in relation to individual lung capacity (Wigmore, Patrick and Libman 221).This variation therefore only requires five seconds of blowing for individuals with small lung capacities and utmost 15 seconds for individuals with large lung capacities (Wigmore, Patrick and Libman 221).

The Intoxilyzer 5000C moreover uses a mechanical chopper to evaluate the amount of liquor in the breath. Working with the mechanical chopper is the tungsten lamp and the internal slip printer, which all work together for the analysis, calibration and printing of the result slip (Wigmore, Patrick and Libman 219). This analysis is largely for the moisture from the lungs, and therefore the need for the five to 15 seconds blowing on the mouthpiece for the moisture from the lungs.

The Intoxilyzer 5000C has been a source controversy given its assumptions and margin of error, even as it costs $7500. The instrument produces breath liquor results matching the blood alcohol sample. This assumption conveys partitioning of alcohol from the blood into the breath at a ratio of 2100:1 (Rose and Furton 1). This assumption does not take into consideration that other individuals have low partition ratios of even 834:1, and therefore overestimate alcohol concentration for such individuals. The Intoxilyzer 5000C has an error margin of +/- 0.010 in relation to the reference sample, and a +/- 0.020 for the breath sample. Studies on subjects have also relayed the uncertainty in the evidential readings of the machine, with +/- 27 percent uncertainty for subjects in the post absorptive state; this is in addition to overestimation of 23 percent of the subjects’ blood-alcohol concentrations being overestimated by 6.8 percent (Rose and Stephan 1).

The Intoxilyzer 9000 on the other hand, in an improvement of the Intoxilyzer 5000C. The machine has a four-filter IR, and measures C-O vibrations in the 9-micron region (GBI Crime Laboratory 6). The four filter wavelengths for the analysis of samples, therefore ensuring better performance in accuracy, precision and the detection of interferants. This, the machine does, using its pulsed infrared technology, which in essence eliminates chopper motors or mechanical filter in the system of analysis.  The machine additionally has a specific detector, and therefore the lack of necessity for a filter wheel. A laboratory evaluation score summary of the performance of the Intoxilyzer 9000C against other machines put Intoxilyzer 9000 at the top of the list, scoring 283 against 266 and 145 for the Evidenzer 240 Mobile and Data master DMT-GF respectively (see table 1) (GBI Crime Laboratory 28).

Category Intoxilyzer 9000 Evidenzer 240


Datamaster DMT-


Linear Dynamic


40 48 24
Environmental Conditions Test 14 14 4
Specificity Test


129 84 77
Mouth Alcohol Test


20 45 10
Sampling Parameter Evaluation 40 30 10
RFI Detection Evaluation 15 15 15
Instrument Stability Evaluation 25 30 5


266 145

Laboratory evaluation Score summary (GBI Crime Laboratory 28)

In its appearance, the Intoxilyzer 9000 spots a full color 8.4 inch touch screen LCD and runs Windows CE, with an operating temperature of 32-1040F (GBI Crime Laboratory 6). The color touch screen helps in ease of operation of the machine, as well as the display of the necessary information during the test process. The machine itself weighs 10lb, with an additional 2lb of the dry gas compartment. Further, it measures 19”x14”x6.5-9.5” for the length, width and height respectively. The machine further, has a slot for the recording card, and therefore produces the card with information on the subject and the test done.

The instrument has a +/- 3 percent accuracy, or a +/- 0.003 g/210L (GBI Crime Laboratory 6). However, whichever is greater between the two is used for accuracy measures. Its precision is additionally 0.003g/201L or less. With such high accuracy measures, the instrument costs $7000 for its base model. Other additional options however, increase the cost with an additional $850for printer or dry gas delivery system and mouthpieces that cost $0.25 per piece. Additionally, the Intoxilyzer 9000 has USB slots or the keyboard, a data connection port for Ethernet connection, as well as other periphery connection slots. The Ethernet connection slots therefore mean that information cannot only be sent to the centralized server, but the machine’s software can also receive software updates from the centralized server over data connection. Data entry is possible via the attached keyboard, the touch screen and magnetic swipe attachment (signature pad) for swiping drivers’ licenses as well as the operator’s authorization information. In performing the test, the machine begins with a two-minute warm-up period. During this period, the machine prepares for the 20-minute evidential Breath Alcohol Test (EBAT), which will require the subject to breath into the mouthpiece and await the test results. 

The Intoxilyzer 5000C and Intoxilyzer 9000 have likenesses and differences in their working. Among the similarities is the ability to print out the test results, although from different sets of printers. Additionally, both require blowing into the mouthpieces for intake of test samples for analysis. Further, both Intoxilyzer 5000C and Intoxilyzer 9000 use keyboards for data entry into the machine. The differences on the other hand, are stark between Intoxilyzer 5000C and Intoxilyzer 9000, with the Intoxilyzer 9000 improving the performance of the Intoxilyzer 5000C massively.

One of the differences between the two is the variety in data entry. Thus, while the Intoxilyzer 5000C allows data entry using only the keyboard, the Intoxilyzer 9000 has a more interactive data entry and user interface via the full color touch screen. This is evidently different from the simplistic data display screen on the Intoxilyzer 5000C. Moreover, the Intoxilyzer 9000 allows for even more peripheries in data entry such as the signature pad for swiping the subject’s driver license, as well as for authentication purposes.

The Intoxilyzer 5000C has three valves and a pump, which have to run self-diagnostic tests at the turning on of the machine (Wigmore, Patrick and Libman 219). The tests in essence have to be performed at every turning on of the machine. On the other hand, the Intoxilyzer 9000 has an inbuilt dry gas calibration, which allows the machine to perform scheduled checks. Such automatic calibrations are instrumental for setting the machine for different environments. Additionally, with multiple calibrations, as is with the Intoxilyzer 9000, the instrument is well equipped to handle both dry and wet ethanol gas standards, as opposed to the wet standards measured by the Intoxilyzer 5000C.

The Intoxilyzer 5000C records information (test results) on the result slip embedded within the machine. This information is physically keyed in by the operator and printed after the completion of the verification process (Wigmore, Patrick and Libman 218). The card is consequently the only source of information for the user’s sample. In contrast, the Intoxilyzer 9000 has the ability to retain the information in its 512 MB Nand Flash, with the capacity for expansion up to 32 GB. It is possible to download this information to the centralized server. Moreover, the machine can print the test, control and calibration information directly from an attached printer. The Intoxilyzer 5000C’s limited capacity only allows it to retain the last test run and nothing more.

Given that the Intoxilyzer 9000 has an operating system and Ethernet connection slots (GBI Crime Laboratory 6), it can therefore receive software updates for its operating system from the server via an internet connection. This allows flexibility and timeliness in software update and therefore improving the machine’s performance. The Intoxilyzer 5000C on the other hand, requires the physical removal and change of the EPROM on its CPU for any software updates and performance improvement.

Moreover, while the base cost of the Intoxilyzer 5000C is $7500, the Intoxilyzer 9000 costs $7000. This is however not inclusive of other peripherals for the Intoxilyzer 9000 such as the printer, dry gas delivery system and mouthpieces, which are $0.25 each (GBI Crime Laboratory 7). The Intoxilyzer 5000C cost also requires the purchase of special print cards given that it utilizes an internal printer as opposed to the presence of an internal printer for the Intoxilyzer 9000, as well as an option for an external USB printer, which is customizable to print different formats including pressure and BrAC curves for individual tests.

The Intoxilyzer 9000 dramatically improves on the operations of Intoxilyzer 5000C. It brings with it capabilities previously absent in the Intoxilyzer 5000C, and therefore improves the speed, accuracy and reliability in getting the level of alcohol content in the blood.  While many defense attorneys still fault the Intoxilyzer 9000, the fact is that the machine provides better and more reliable test results. It also allows for faster access to the information, through the Ethernet connection cable, in addition to saving subject samples for further investigation when need arises. It is perhaps the reliability and accuracy of the machine that has prompted its wide adoption and certification across many statesWork cited

Committee on Identifying the Needs of the Forensic Sciences Community. Strengthening Forensic Science in the United States: A Path Forward. Washington, DC: National Academy of Sciences, 2009

GBI Crime Laboratory. Evaluation of Breath Alcohol Testing Instruments to Replace the Intoxilyzer 5000. Georgia: GBI Division of Forensic Sciences, 2009

Rose, Stephan & Furton, Kenneth, G. Variables Affecting the Accuracy and Precision of Breath Alcohol Instruments Including the Intoxilyzer 5000C. Miami, Florida: Florida International University, n.d.

Watterson, James, H. “Assessment of Response of the Intoxilyzer® 8000C to Volatiles of Forensic Relevance In Vitro, Part I: Acetone, Isopropanol, and Methanol.” Journal of Analytical Toxicology, 33(2009): 109-117

Wigmore, J. G., Patrick, Jeff & Libman, Rick. “Evidentiary IR Breath Testing/Intoxilyzer 5000C.” Journal of Motor Vehicle Law, 7.3 (1996): 203-228